Add support for OpenSSL

Uses work by @hrxi in https://github.com/dino/dino/pull/1515

Co-Authored-By: hrxi <hrrrxi@gmail.com>

33 files changed, 2099 insertions, 729 deletions

diff --git a/crypto-vala/meson.build b/crypto-vala/meson.build
index fdd08f87..bc66fbf9 100644
--- a/crypto-vala/meson.build
+++ b/crypto-vala/meson.build
@@ -1,14 +1,12 @@
 dependencies = [
     dep_gio,
     dep_glib,
-    dep_libgcrypt,
     dep_libsrtp2,
 ]
 sources = files(
     'src/cipher.vala',
     'src/cipher_converter.vala',
     'src/error.vala',
-    'src/random.vala',
     'src/srtp.vala',
 )
 c_args = vala_c_args + [
@@ -17,6 +15,19 @@ c_args = vala_c_args + [
 vala_args = [
     '--vapidir', meson.current_source_dir() / 'vapi',
 ]
+if crypto_backend == 'gnutls'
+    dependencies += [ dep_libgcrypt ]
+    sources += files(
+        'src/gcrypt.vala',
+        'src/cipher_gcrypt.vala',
+    )
+else # openssl
+    dependencies += [ dep_openssl ]
+    sources += files(
+        'src/openssl.vala',
+        'src/cipher_openssl.vala',
+    )
+endif
 lib_crypto_vala = library('crypto-vala', sources, c_args: c_args, vala_args: vala_args, dependencies: dependencies, version: '0.0', install: true, install_dir: [true, true, true], install_rpath: default_install_rpath)
 dep_crypto_vala = declare_dependency(link_with: lib_crypto_vala, include_directories: include_directories('.'))
 
diff --git a/crypto-vala/src/cipher.vala b/crypto-vala/src/cipher.vala
index 306dafa8..f7aee100 100644
--- a/crypto-vala/src/cipher.vala
+++ b/crypto-vala/src/cipher.vala
@@ -1,152 +1,19 @@
 namespace Crypto {
-public class SymmetricCipher {
-    private GCrypt.Cipher.Cipher cipher;
 
-    public static bool supports(string algo_name) {
-        GCrypt.Cipher.Algorithm algo;
-        GCrypt.Cipher.Mode mode;
-        GCrypt.Cipher.Flag flags;
-        return parse(algo_name, out algo, out mode, out flags);
-    }
-
-    private static unowned string mode_to_string(GCrypt.Cipher.Mode mode) {
-        switch (mode) {
-            case GCrypt.Cipher.Mode.ECB: return "ECB";
-            case GCrypt.Cipher.Mode.CFB: return "CFB";
-            case GCrypt.Cipher.Mode.CBC: return "CBC";
-            case GCrypt.Cipher.Mode.STREAM: return "STREAM";
-            case GCrypt.Cipher.Mode.OFB: return "OFB";
-            case GCrypt.Cipher.Mode.CTR: return "CTR";
-            case GCrypt.Cipher.Mode.AESWRAP: return "AESWRAP";
-            case GCrypt.Cipher.Mode.GCM: return "GCM";
-            case GCrypt.Cipher.Mode.POLY1305: return "POLY1305";
-            case GCrypt.Cipher.Mode.OCB: return "OCB";
-            case GCrypt.Cipher.Mode.CFB8: return "CFB8";
-            // case GCrypt.Cipher.Mode.XTS: return "XTS"; // Not supported in gcrypt < 1.8
-        }
-        return "NONE";
-    }
-
-    private static GCrypt.Cipher.Mode mode_from_string(string name) {
-        switch (name) {
-            case "ECB": return GCrypt.Cipher.Mode.ECB;
-            case "CFB": return GCrypt.Cipher.Mode.CFB;
-            case "CBC": return GCrypt.Cipher.Mode.CBC;
-            case "STREAM": return GCrypt.Cipher.Mode.STREAM;
-            case "OFB": return GCrypt.Cipher.Mode.OFB;
-            case "CTR": return GCrypt.Cipher.Mode.CTR;
-            case "AESWRAP": return GCrypt.Cipher.Mode.AESWRAP;
-            case "GCM": return GCrypt.Cipher.Mode.GCM;
-            case "POLY1305": return GCrypt.Cipher.Mode.POLY1305;
-            case "OCB": return GCrypt.Cipher.Mode.OCB;
-            case "CFB8": return GCrypt.Cipher.Mode.CFB8;
-            // case "XTS": return GCrypt.Cipher.Mode.XTS; // Not supported in gcrypt < 1.8
-        }
-        return GCrypt.Cipher.Mode.NONE;
-    }
-
-    private static string flags_to_string(GCrypt.Cipher.Flag flags) {
-        string? s = null;
-        if ((GCrypt.Cipher.Flag.CBC_MAC & flags) != 0) s = (s == null ? "" : @"$s-") + "MAC";
-        if ((GCrypt.Cipher.Flag.CBC_CTS & flags) != 0) s = (s == null ? "" : @"$s-") + "CTS";
-        if ((GCrypt.Cipher.Flag.ENABLE_SYNC & flags) != 0) s = (s == null ? "" : @"$s-") + "SYNC";
-        if ((GCrypt.Cipher.Flag.SECURE & flags) != 0) s = (s == null ? "" : @"$s-") + "SECURE";
-        return s ?? "NONE";
-    }
-
-    private static GCrypt.Cipher.Flag flag_from_string(string flag_name) {
-        if (flag_name == "SECURE") return GCrypt.Cipher.Flag.SECURE;
-        if (flag_name == "SYNC") return GCrypt.Cipher.Flag.ENABLE_SYNC;
-        if (flag_name == "CTS") return GCrypt.Cipher.Flag.CBC_CTS;
-        if (flag_name == "MAC") return GCrypt.Cipher.Flag.CBC_MAC;
-        return 0;
-    }
-
-    private static GCrypt.Cipher.Flag flags_from_string(string flag_names) {
-        GCrypt.Cipher.Flag flags = 0;
-        foreach(string flag in flag_names.split("-")) {
-            flags |= flag_from_string(flag);
-        }
-        return flags;
-    }
-
-    private static bool parse(string algo_name, out GCrypt.Cipher.Algorithm algo, out GCrypt.Cipher.Mode mode, out GCrypt.Cipher.Flag flags) {
-        algo = GCrypt.Cipher.Algorithm.NONE;
-        mode = GCrypt.Cipher.Mode.NONE;
-        flags = 0;
-        string[] algo_parts = algo_name.split("-", 3);
-
-        algo = GCrypt.Cipher.Algorithm.from_string(algo_parts[0]);
-        if (algo_parts.length >= 2) {
-            mode = mode_from_string(algo_parts[1]);
-        }
-        if (algo_parts.length == 3) {
-            flags |= flags_from_string(algo_parts[2]);
-        }
-        return to_algo_name(algo, mode, flags) == algo_name;
-    }
-
-    private static string to_algo_name(GCrypt.Cipher.Algorithm algo = GCrypt.Cipher.Algorithm.NONE, GCrypt.Cipher.Mode mode = GCrypt.Cipher.Mode.NONE, GCrypt.Cipher.Flag flags = 0) {
-        if (flags != 0) {
-            return @"$algo-$(mode_to_string(mode))-$(flags_to_string(flags))";
-        } else if (mode != GCrypt.Cipher.Mode.NONE) {
-            return @"$algo-$(mode_to_string(mode))";
-        } else {
-            return algo.to_string();
-        }
-    }
-
-    public SymmetricCipher(string algo_name) throws Error {
-        GCrypt.Cipher.Algorithm algo;
-        GCrypt.Cipher.Mode mode;
-        GCrypt.Cipher.Flag flags;
-        if (parse(algo_name, out algo, out mode, out flags)) {
-            this.gcrypt(algo, mode, flags);
-        } else {
-            throw new Error.ILLEGAL_ARGUMENTS(@"The algorithm $algo_name is not supported");
-        }
-    }
-
-    private SymmetricCipher.gcrypt(GCrypt.Cipher.Algorithm algo, GCrypt.Cipher.Mode mode, GCrypt.Cipher.Flag flags) throws Error {
-        may_throw_gcrypt_error(GCrypt.Cipher.Cipher.open(out this.cipher, algo, mode, flags));
-    }
-
-    public void set_key(uint8[] key) throws Error {
-        may_throw_gcrypt_error(cipher.set_key(key));
-    }
-
-    public void set_iv(uint8[] iv) throws Error {
-        may_throw_gcrypt_error(cipher.set_iv(iv));
-    }
-
-    public void set_counter_vector(uint8[] ctr) throws Error {
-        may_throw_gcrypt_error(cipher.set_counter_vector(ctr));
-    }
-
-    public void reset() throws Error {
-        may_throw_gcrypt_error(cipher.reset());
-    }
-
-    public uint8[] get_tag(size_t taglen) throws Error {
-        uint8[] tag = new uint8[taglen];
-        may_throw_gcrypt_error(cipher.get_tag(tag));
-        return tag;
-    }
-
-    public void check_tag(uint8[] tag) throws Error {
-        may_throw_gcrypt_error(cipher.check_tag(tag));
-    }
-
-    public void encrypt(uint8[] output, uint8[] input) throws Error {
-        may_throw_gcrypt_error(cipher.encrypt(output, input));
-    }
+public interface SymmetricCipher {
+    public abstract void set_key(uint8[] key) throws Error;
+    public abstract void set_iv(uint8[] iv) throws Error;
+    public abstract void reset() throws Error;
+}
 
-    public void decrypt(uint8[] output, uint8[] input) throws Error {
-        may_throw_gcrypt_error(cipher.decrypt(output, input));
-    }
+public interface SymmetricCipherEncryption : SymmetricCipher, Object {
+    public abstract int encrypt(uint8[] output, uint8[] input) throws Error;
+    public abstract uint8[] get_tag(size_t taglen) throws Error;
+}
 
-    public void sync() throws Error {
-        may_throw_gcrypt_error(cipher.sync());
-    }
+public interface SymmetricCipherDecryption : SymmetricCipher, Object {
+    public abstract int decrypt(uint8[] output, uint8[] input) throws Error;
+    public abstract void check_tag(uint8[] tag) throws Error;
 }
+
 }
diff --git a/crypto-vala/src/cipher_converter.vala b/crypto-vala/src/cipher_converter.vala
index 5fb1f548..49e7af71 100644
--- a/crypto-vala/src/cipher_converter.vala
+++ b/crypto-vala/src/cipher_converter.vala
@@ -1,18 +1,14 @@
 using GLib;
 
 namespace Crypto {
-public abstract class SymmetricCipherConverter : Converter, Object {
-    internal SymmetricCipher cipher;
-    internal size_t attached_taglen;
 
-    public abstract ConverterResult convert(uint8[] inbuf, uint8[] outbuf, ConverterFlags flags, out size_t bytes_read, out size_t bytes_written) throws IOError;
+public class SymmetricCipherEncrypter : Converter, Object {
+    private SymmetricCipherEncryption cipher;
+    private size_t attached_taglen;
 
-    public uint8[] get_tag(size_t taglen) throws Error {
-        return cipher.get_tag(taglen);
-    }
-
-    public void check_tag(uint8[] tag) throws Error {
-        cipher.check_tag(tag);
+    public SymmetricCipherEncrypter(owned SymmetricCipherEncryption cipher, size_t attached_taglen = 0) {
+        this.cipher = (owned) cipher;
+        this.attached_taglen = attached_taglen;
     }
 
     public void reset() {
@@ -22,15 +18,12 @@ public abstract class SymmetricCipherConverter : Converter, Object {
             warning(@"$(e.domain) error while resetting cipher: $(e.message)");
         }
     }
-}
 
-public class SymmetricCipherEncrypter : SymmetricCipherConverter {
-    public SymmetricCipherEncrypter(owned SymmetricCipher cipher, size_t attached_taglen = 0) {
-        this.cipher = (owned) cipher;
-        this.attached_taglen = attached_taglen;
+    public uint8[] get_tag(size_t taglen) throws Error {
+        return ((SymmetricCipherEncryption)cipher).get_tag(taglen);
     }
 
-    public override ConverterResult convert(uint8[] inbuf, uint8[] outbuf, ConverterFlags flags, out size_t bytes_read, out size_t bytes_written) throws IOError {
+    public ConverterResult convert(uint8[] inbuf, uint8[] outbuf, ConverterFlags flags, out size_t bytes_read, out size_t bytes_written) throws IOError {
         if (inbuf.length > outbuf.length) {
             throw new IOError.NO_SPACE("CipherConverter needs at least the size of input as output space");
         }
@@ -39,7 +32,7 @@ public class SymmetricCipherEncrypter : SymmetricCipherConverter {
         }
         try {
             if (inbuf.length > 0) {
-                cipher.encrypt(outbuf, inbuf);
+                ((SymmetricCipherEncryption)cipher).encrypt(outbuf, inbuf);
             }
             bytes_read = inbuf.length;
             bytes_written = inbuf.length;
@@ -60,13 +53,28 @@ public class SymmetricCipherEncrypter : SymmetricCipherConverter {
     }
 }
 
-public class SymmetricCipherDecrypter : SymmetricCipherConverter {
-    public SymmetricCipherDecrypter(owned SymmetricCipher cipher, size_t attached_taglen = 0) {
+public class SymmetricCipherDecrypter : Converter, Object {
+    private SymmetricCipherDecryption cipher;
+    private size_t attached_taglen;
+
+    public SymmetricCipherDecrypter(owned SymmetricCipherDecryption cipher, size_t attached_taglen = 0) {
         this.cipher = (owned) cipher;
         this.attached_taglen = attached_taglen;
     }
 
-    public override ConverterResult convert(uint8[] inbuf, uint8[] outbuf, ConverterFlags flags, out size_t bytes_read, out size_t bytes_written) throws IOError {
+    public void reset() {
+        try {
+            cipher.reset();
+        } catch (Crypto.Error e) {
+            warning(@"$(e.domain) error while resetting cipher: $(e.message)");
+        }
+    }
+
+    public void check_tag(uint8[] tag) throws Error {
+        ((SymmetricCipherDecryption)cipher).check_tag(tag);
+    }
+
+    public ConverterResult convert(uint8[] inbuf, uint8[] outbuf, ConverterFlags flags, out size_t bytes_read, out size_t bytes_written) throws IOError {
         if (inbuf.length > outbuf.length + attached_taglen) {
             throw new IOError.NO_SPACE("CipherConverter needs at least the size of input as output space");
         }
@@ -78,7 +86,7 @@ public class SymmetricCipherDecrypter : SymmetricCipherConverter {
         try {
             inbuf.length -= (int) attached_taglen;
             if (inbuf.length > 0) {
-                cipher.decrypt(outbuf, inbuf);
+                ((SymmetricCipherDecryption)cipher).decrypt(outbuf, inbuf);
             }
             bytes_read = inbuf.length;
             bytes_written = inbuf.length;
diff --git a/crypto-vala/src/cipher_gcrypt.vala b/crypto-vala/src/cipher_gcrypt.vala
new file mode 100644
index 00000000..3e811d29
--- /dev/null
+++ b/crypto-vala/src/cipher_gcrypt.vala
@@ -0,0 +1,137 @@
+namespace Crypto {
+
+internal class SymmetricCipherGcrypt : SymmetricCipher, SymmetricCipherEncryption, SymmetricCipherDecryption, Object {
+    private GCrypt.Cipher.Cipher cipher;
+
+    private static unowned string mode_to_string(GCrypt.Cipher.Mode mode) {
+        switch (mode) {
+            case GCrypt.Cipher.Mode.ECB: return "ECB";
+            case GCrypt.Cipher.Mode.CFB: return "CFB";
+            case GCrypt.Cipher.Mode.CBC: return "CBC";
+            case GCrypt.Cipher.Mode.STREAM: return "STREAM";
+            case GCrypt.Cipher.Mode.OFB: return "OFB";
+            case GCrypt.Cipher.Mode.CTR: return "CTR";
+            case GCrypt.Cipher.Mode.AESWRAP: return "AESWRAP";
+            case GCrypt.Cipher.Mode.GCM: return "GCM";
+            case GCrypt.Cipher.Mode.POLY1305: return "POLY1305";
+            case GCrypt.Cipher.Mode.OCB: return "OCB";
+            case GCrypt.Cipher.Mode.CFB8: return "CFB8";
+            // case GCrypt.Cipher.Mode.XTS: return "XTS"; // Not supported in gcrypt < 1.8
+        }
+        return "NONE";
+    }
+
+    private static GCrypt.Cipher.Mode mode_from_string(string name) {
+        switch (name) {
+            case "ECB": return GCrypt.Cipher.Mode.ECB;
+            case "CFB": return GCrypt.Cipher.Mode.CFB;
+            case "CBC": return GCrypt.Cipher.Mode.CBC;
+            case "STREAM": return GCrypt.Cipher.Mode.STREAM;
+            case "OFB": return GCrypt.Cipher.Mode.OFB;
+            case "CTR": return GCrypt.Cipher.Mode.CTR;
+            case "AESWRAP": return GCrypt.Cipher.Mode.AESWRAP;
+            case "GCM": return GCrypt.Cipher.Mode.GCM;
+            case "POLY1305": return GCrypt.Cipher.Mode.POLY1305;
+            case "OCB": return GCrypt.Cipher.Mode.OCB;
+            case "CFB8": return GCrypt.Cipher.Mode.CFB8;
+            // case "XTS": return GCrypt.Cipher.Mode.XTS; // Not supported in gcrypt < 1.8
+        }
+        return GCrypt.Cipher.Mode.NONE;
+    }
+
+    private static string flags_to_string(GCrypt.Cipher.Flag flags) {
+        string? s = null;
+        if ((GCrypt.Cipher.Flag.CBC_MAC & flags) != 0) s = (s == null ? "" : @"$s-") + "MAC";
+        if ((GCrypt.Cipher.Flag.CBC_CTS & flags) != 0) s = (s == null ? "" : @"$s-") + "CTS";
+        if ((GCrypt.Cipher.Flag.ENABLE_SYNC & flags) != 0) s = (s == null ? "" : @"$s-") + "SYNC";
+        if ((GCrypt.Cipher.Flag.SECURE & flags) != 0) s = (s == null ? "" : @"$s-") + "SECURE";
+        return s ?? "NONE";
+    }
+
+    private static GCrypt.Cipher.Flag flag_from_string(string flag_name) {
+        if (flag_name == "SECURE") return GCrypt.Cipher.Flag.SECURE;
+        if (flag_name == "SYNC") return GCrypt.Cipher.Flag.ENABLE_SYNC;
+        if (flag_name == "CTS") return GCrypt.Cipher.Flag.CBC_CTS;
+        if (flag_name == "MAC") return GCrypt.Cipher.Flag.CBC_MAC;
+        return 0;
+    }
+
+    private static GCrypt.Cipher.Flag flags_from_string(string flag_names) {
+        GCrypt.Cipher.Flag flags = 0;
+        foreach(string flag in flag_names.split("-")) {
+            flags |= flag_from_string(flag);
+        }
+        return flags;
+    }
+
+    private static bool parse(string algo_name, out GCrypt.Cipher.Algorithm algo, out GCrypt.Cipher.Mode mode, out GCrypt.Cipher.Flag flags) {
+        algo = GCrypt.Cipher.Algorithm.NONE;
+        mode = GCrypt.Cipher.Mode.NONE;
+        flags = 0;
+        string[] algo_parts = algo_name.split("-", 3);
+
+        algo = GCrypt.Cipher.Algorithm.from_string(algo_parts[0]);
+        if (algo_parts.length >= 2) {
+            mode = mode_from_string(algo_parts[1]);
+        }
+        if (algo_parts.length == 3) {
+            flags |= flags_from_string(algo_parts[2]);
+        }
+        return to_algo_name(algo, mode, flags) == algo_name;
+    }
+
+    private static string to_algo_name(GCrypt.Cipher.Algorithm algo = GCrypt.Cipher.Algorithm.NONE, GCrypt.Cipher.Mode mode = GCrypt.Cipher.Mode.NONE, GCrypt.Cipher.Flag flags = 0) {
+        if (flags != 0) {
+            return @"$algo-$(mode_to_string(mode))-$(flags_to_string(flags))";
+        } else if (mode != GCrypt.Cipher.Mode.NONE) {
+            return @"$algo-$(mode_to_string(mode))";
+        } else {
+            return algo.to_string();
+        }
+    }
+
+    public SymmetricCipherGcrypt(string algo_name) throws Error {
+        GCrypt.Cipher.Algorithm algo;
+        GCrypt.Cipher.Mode mode;
+        GCrypt.Cipher.Flag flags;
+        if (parse(algo_name, out algo, out mode, out flags)) {
+            may_throw_gcrypt_error(GCrypt.Cipher.Cipher.open(out this.cipher, algo, mode, flags));
+        } else {
+            throw new Error.ILLEGAL_ARGUMENTS(@"The algorithm $algo_name is not supported");
+        }
+    }
+
+    public void set_key(uint8[] key) throws Error {
+        may_throw_gcrypt_error(cipher.set_key(key));
+    }
+
+    public void set_iv(uint8[] iv) throws Error {
+        may_throw_gcrypt_error(cipher.set_iv(iv));
+    }
+
+    public void reset() throws Error {
+        may_throw_gcrypt_error(cipher.reset());
+    }
+
+    public uint8[] get_tag(size_t taglen) throws Error {
+        uint8[] tag = new uint8[taglen];
+        may_throw_gcrypt_error(cipher.get_tag(tag));
+        return tag;
+    }
+
+    public void check_tag(uint8[] tag) throws Error {
+        may_throw_gcrypt_error(cipher.check_tag(tag));
+    }
+
+    public int encrypt(uint8[] output, uint8[] input) throws Error {
+        may_throw_gcrypt_error(cipher.encrypt(output, input));
+        return input.length;
+    }
+
+    public int decrypt(uint8[] output, uint8[] input) throws Error {
+        may_throw_gcrypt_error(cipher.decrypt(output, input));
+        return input.length;
+    }
+}
+
+}
diff --git a/crypto-vala/src/cipher_openssl.vala b/crypto-vala/src/cipher_openssl.vala
new file mode 100644
index 00000000..75a0ef9a
--- /dev/null
+++ b/crypto-vala/src/cipher_openssl.vala
@@ -0,0 +1,156 @@
+namespace Crypto {
+
+internal class SymmetricCipherEncryptionOpenssl : SymmetricCipher, SymmetricCipherEncryption, Object {
+    private OpenSSL.EVP.CipherContext? cipher;
+    private bool is_finalized = false;
+
+    public SymmetricCipherEncryptionOpenssl(string algo_name) throws Error {
+        if (algo_name != "AES-GCM") throw new Error.ILLEGAL_ARGUMENTS(@"The algorithm $algo_name is not supported");
+        cipher = new OpenSSL.EVP.CipherContext();
+    }
+
+    public void set_key(uint8[] key) throws Error {
+        unowned OpenSSL.EVP.Cipher algo;
+        if (key.length == 16) {
+            algo = OpenSSL.EVP.aes_128_gcm();
+        } else if (key.length == 32) {
+            algo = OpenSSL.EVP.aes_256_gcm();
+        } else {
+            throw new Crypto.Error.ILLEGAL_ARGUMENTS("key length must be 16 or 32 for AES-GCM");
+        }
+        try {
+            cipher.encrypt_init(algo, null, null);
+            cipher.encrypt_init(null, key, null);
+        } catch (GLib.Error e) {
+            throw new Crypto.Error.OPENSSL(e.message);
+        }
+    }
+
+    public void set_iv(uint8[] iv) throws Error {
+        if (iv.length != 12) {
+            cipher.ctrl(OpenSSL.EVP.Control.GCM_SET_IVLEN, iv.length, null);
+        }
+        try {
+            cipher.encrypt_init(null, null, iv);
+        } catch (GLib.Error e) {
+            throw new Crypto.Error.OPENSSL(e.message);
+        }
+    }
+
+    public void reset() throws Error {
+        throw new Crypto.Error.ILLEGAL_ARGUMENTS("can't reset OpenSSL cipher context");
+    }
+
+    public uint8[] get_tag(size_t taglen) throws Error {
+        uint8[] tag = new uint8[taglen];
+        if (!is_finalized) {
+            uint8[] empty = new uint8[0];
+            int empty_len = 0;
+            try {
+                cipher.encrypt_final(empty, out empty_len);
+            } catch (GLib.Error e) {
+                throw new Crypto.Error.OPENSSL(e.message);
+            }
+            if (empty_len != 0) {
+                throw new Crypto.Error.ILLEGAL_ARGUMENTS("get_tag called on a stream with remaining data");
+            }
+        }
+        if (cipher.ctrl(OpenSSL.EVP.Control.GCM_GET_TAG, (int)taglen, tag) != 1) {
+            openssl_error();
+        }
+        return tag;
+    }
+
+    public int encrypt(uint8[] output, uint8[] input) throws Error {
+        int output_length = output.length;
+        if (is_finalized) {
+            throw new Crypto.Error.ILLEGAL_ARGUMENTS("encrypt called after get_tag");
+        }
+        try {
+            cipher.encrypt_update(output, out output_length, input);
+        } catch (GLib.Error e) {
+            throw new Crypto.Error.OPENSSL(e.message);
+        }
+        return output_length;
+    }
+}
+
+internal class SymmetricCipherDecryptionOpenssl : SymmetricCipher, SymmetricCipherDecryption, Object {
+    private OpenSSL.EVP.CipherContext? cipher;
+    private bool is_finalized = false;
+
+    public SymmetricCipherDecryptionOpenssl(string algo_name) throws Error {
+        if (algo_name != "AES-GCM") throw new Error.ILLEGAL_ARGUMENTS(@"The algorithm $algo_name is not supported");
+        cipher = new OpenSSL.EVP.CipherContext();
+        try {
+            cipher.decrypt_init(OpenSSL.EVP.aes_128_gcm(), null, null);
+        } catch (GLib.Error e) {
+            throw new Crypto.Error.OPENSSL(e.message);
+        }
+    }
+
+    public void set_key(uint8[] key) throws Error {
+        unowned OpenSSL.EVP.Cipher algo;
+        if (key.length == 16) {
+            algo = OpenSSL.EVP.aes_128_gcm();
+        } else if (key.length == 32) {
+            algo = OpenSSL.EVP.aes_256_gcm();
+        } else {
+            throw new Crypto.Error.ILLEGAL_ARGUMENTS("key length must be 16 or 32 for AES-GCM");
+        }
+        try {
+            cipher.decrypt_init(algo, null, null);
+            cipher.decrypt_init(null, key, null);
+        } catch (GLib.Error e) {
+            throw new Crypto.Error.OPENSSL(e.message);
+        }
+    }
+
+    public void set_iv(uint8[] iv) throws Error {
+        if (iv.length != 12) {
+            cipher.ctrl(OpenSSL.EVP.Control.GCM_SET_IVLEN, iv.length, null);
+        }
+        try {
+            cipher.decrypt_init(null, null, iv);
+        } catch (GLib.Error e) {
+            throw new Crypto.Error.OPENSSL(e.message);
+        }
+    }
+
+    public void reset() throws Error {
+        throw new Crypto.Error.ILLEGAL_ARGUMENTS("can't reset OpenSSL cipher context");
+    }
+
+    public void check_tag(uint8[] tag) throws Error {
+        if (cipher.ctrl(OpenSSL.EVP.Control.GCM_SET_TAG, tag.length, tag) != 1) {
+            openssl_error();
+        }
+        if (!is_finalized) {
+            uint8[] empty = new uint8[0];
+            int empty_len = 0;
+            try {
+                cipher.decrypt_final(empty, out empty_len);
+            } catch (GLib.Error e) {
+                throw new Crypto.Error.OPENSSL(e.message);
+            }
+            if (empty_len != 0) {
+                throw new Crypto.Error.ILLEGAL_ARGUMENTS("check_tag called on a stream with remaining data");
+            }
+        }
+    }
+
+    public int decrypt(uint8[] output, uint8[] input) throws Error {
+        if (is_finalized) {
+            throw new Crypto.Error.ILLEGAL_ARGUMENTS("decrypt called after check_tag");
+        }
+        int output_length = output.length;
+        try {
+            cipher.decrypt_update(output, out output_length, input);
+        } catch (GLib.Error e) {
+            throw new Crypto.Error.OPENSSL(e.message);
+        }
+        return output_length;
+    }
+}
+
+}
diff --git a/crypto-vala/src/error.vala b/crypto-vala/src/error.vala
index 5007d725..a26f39c3 100644
--- a/crypto-vala/src/error.vala
+++ b/crypto-vala/src/error.vala
@@ -3,13 +3,9 @@ namespace Crypto {
 public errordomain Error {
     ILLEGAL_ARGUMENTS,
     GCRYPT,
+    OPENSSL,
     AUTHENTICATION_FAILED,
     UNKNOWN
 }
 
-internal void may_throw_gcrypt_error(GCrypt.Error e) throws Error {
-    if (((int)e) != 0) {
-        throw new Crypto.Error.GCRYPT(e.to_string());
-    }
 }
-}
\ No newline at end of file
diff --git a/crypto-vala/src/gcrypt.vala b/crypto-vala/src/gcrypt.vala
new file mode 100644
index 00000000..1997a5e1
--- /dev/null
+++ b/crypto-vala/src/gcrypt.vala
@@ -0,0 +1,21 @@
+namespace Crypto {
+
+public static void randomize(uint8[] buffer) {
+    GCrypt.Random.randomize(buffer);
+}
+
+internal void may_throw_gcrypt_error(GCrypt.Error e) throws Error {
+    if (((int)e) != 0) {
+        throw new Crypto.Error.GCRYPT(e.to_string());
+    }
+}
+
+public SymmetricCipherEncryption create_symmetric_cipher_encryption(string algo_name) throws Error {
+    return new SymmetricCipherGcrypt(algo_name);
+}
+
+public SymmetricCipherDecryption create_symmetric_cipher_decryption(string algo_name) throws Error {
+    return new SymmetricCipherGcrypt(algo_name);
+}
+
+}
diff --git a/crypto-vala/src/openssl.vala b/crypto-vala/src/openssl.vala
new file mode 100644
index 00000000..4a288467
--- /dev/null
+++ b/crypto-vala/src/openssl.vala
@@ -0,0 +1,19 @@
+namespace Crypto {
+
+public static void randomize(uint8[] buffer) {
+    OpenSSL.RAND.bytes(buffer);
+}
+
+internal void openssl_error() throws Error {
+    throw new Crypto.Error.OPENSSL(OpenSSL.ERR.reason_error_string(OpenSSL.ERR.get_error()));
+}
+
+public SymmetricCipherEncryption create_symmetric_cipher_encryption(string algo_name) throws Error {
+    return new SymmetricCipherEncryptionOpenssl(algo_name);
+}
+
+public SymmetricCipherDecryption create_symmetric_cipher_decryption(string algo_name) throws Error {
+    return new SymmetricCipherDecryptionOpenssl(algo_name);
+}
+
+}
diff --git a/crypto-vala/src/random.vala b/crypto-vala/src/random.vala
deleted file mode 100644
index 3f5d3ba9..00000000
--- a/crypto-vala/src/random.vala
+++ /dev/null
@@ -1,5 +0,0 @@
-namespace Crypto {
-public static void randomize(uint8[] buffer) {
-    GCrypt.Random.randomize(buffer);
-}
-}
\ No newline at end of file
diff --git a/crypto-vala/vapi/openssl.vapi b/crypto-vala/vapi/openssl.vapi
new file mode 100644
index 00000000..87693d37
--- /dev/null
+++ b/crypto-vala/vapi/openssl.vapi
@@ -0,0 +1,322 @@
+[CCode (cprefix = "")]
+namespace OpenSSL {
+    [CCode (cprefix = "ASN1_", lower_case_cprefix = "ASN1_", cheader_filename = "openssl/asn1.h")]
+    namespace ASN1 {
+        [Compact]
+        [CCode (cname = "ASN1_INTEGER", lower_case_cprefix = "ASN1_INTEGER_", cprefix = "ASN1_INTEGER_", free_function = "ASN1_INTEGER_free")]
+        public class Integer {
+            public bool @set (long v);
+        }
+
+        [Compact]
+        [CCode (cname = "ASN1_TIME", lower_case_cprefix = "ASN1_TIME_", cprefix = "ASN1_TIME_", copy_function = "ASN1_TIME_dup", free_function = "ASN1_STRING_free")]
+        public class Time {
+            public bool @set (time_t t);
+        }
+    }
+    [Compact]
+    [CCode (cname = "BIO", lower_case_cprefix = "BIO_", cprefix = "BIO_", ref_function = "BIO_up_ref", ref_function_void = true, unref_function = "BIO_free", cheader_filename = "openssl/bio.h", simple_generics = true)]
+    public class BIO<T> {
+        [Compact]
+        [CCode (cname = "BIO_METHOD", lower_case_cprefix = "BIO_meth_", cprefix = "BIO_meth_", unref_function = "BIO_meth_free", simple_generics = true)]
+        public class Method<T> {
+            public Method (Type type, string name);
+            [CCode (has_target = false)]
+            public delegate int WriteFunc<T> (BIO<T> bio, [CCode (type = "const char *", array_length_type = "int")] uint8[] buf);
+            [CCode (has_target = false)]
+            public delegate int ReadFunc<T> (BIO<T> bio, [CCode (type = "char *", array_length_type = "int")] uint8[] out_buf);
+            [CCode (has_target = false, simple_generics = true)]
+            public delegate long CtrlFunc<T> (BIO<T> bio, ControlCommand cmd, long num, void* ptr);
+            public WriteFunc<T> write { get; set; }
+            public ReadFunc<T> read { get; set; }
+            public CtrlFunc<T> ctrl { get; set; }
+        }
+
+        [Flags]
+        [CCode (cname = "int")]
+        public enum Type {
+            SOURCE_SINK,
+            DGRAM,
+        }
+
+        [CCode (cname = "int", cprefix = "BIO_CTRL_", has_type_id = false)]
+        public enum ControlCommand {
+            RESET,
+            EOF,
+            SET,
+            GET,
+            PUSH,
+            POP,
+            GET_CLOSE,
+            SET_CLOSE,
+            PENDING,
+            FLUSH,
+            DUP,
+            WPENDING,
+
+            DGRAM_QUERY_MTU,
+            DGRAM_GET_MTU,
+            DGRAM_SET_MTU,
+            DGRAM_SET_PEER,
+            DGRAM_SET_NEXT_TIMEOUT,
+            DGRAM_GET_PEER,
+            DGRAM_GET_FALLBACK_MTU,
+            DGRAM_SET_DONT_FRAG,
+            DGRAM_GET_MTU_OVERHEAD,
+        }
+
+        public BIO (Method<T> type);
+        public T data { get; set; }
+
+        public void clear_retry_flags ();
+        public void set_retry_read ();
+        public bool should_read ();
+    }
+
+    [CCode (cprefix = "ERR_", lower_case_cprefix = "ERR_", cheader_filename = "openssl/err.h")]
+    namespace ERR {
+        public ulong get_error ();
+        public unowned string lib_error_string (ulong error);
+        public unowned string reason_error_string (ulong error);
+    }
+
+    [CCode (cprefix = "EVP_", lower_case_cprefix = "EVP_", cheader_filename = "openssl/evp.h")]
+    namespace EVP {
+        [Compact]
+        [CCode (cname = "EVP_PKEY", lower_case_cprefix = "EVP_PKEY_", cprefix = "EVP_PKEY_", ref_function = "EVP_PKEY_up_ref", ref_function_void = true, unref_function = "EVP_PKEY_free")]
+        public class Key {
+            public Key ();
+            [CCode (cheader_filename = "openssl_utils.h")]
+            public Key.generate_ecdsa (string curve);
+        }
+        [Compact]
+        [CCode (cname = "EVP_MD", lower_case_cprefix = "EVP_MD_", cprefix = "EVP_MD_", ref_function = "EVP_MD_up_ref", ref_function_void = true, unref_function = "EVP_MD_free")]
+        public class MessageDigest {
+        }
+
+        [Compact]
+        [CCode (cname = "EVP_CIPHER", lower_case_cprefix = "EVP_CIPHER_", cprefix = "EVP_CIPHER_", ref_function = "EVP_CIPHER_up_ref", ref_function_void = true, unref_function = "EVP_CIPHER_free")]
+        public class Cipher {
+
+        }
+
+        [Compact]
+        [CCode (cname = "EVP_CIPHER_CTX", lower_case_cprefix = "EVP_CIPHER_CTX_", cprefix = "EVP_CIPHER_CTX_", free_function = "EVP_CIPHER_CTX_free")]
+        public class CipherContext {
+            public CipherContext ();
+
+            [CCode (simple_generics = true)]
+            public int ctrl<T>(Control cmd, int p1, T? p2);
+
+            [CCode (cname = "EVP_EncryptInit")]
+            private int encrypt_init_ (Cipher? cipher, [CCode (array_length = false)] uint8[]? key, [CCode (array_length = false)] uint8[]? iv);
+            public void encrypt_init (Cipher? cipher, uint8[]? key, uint8[]? iv) throws GLib.Error {
+                throw_if_error (encrypt_init_ (cipher, key, iv));
+            }
+            [CCode (cname = "EVP_EncryptUpdate")]
+            private int encrypt_update_ ([CCode (array_length = false)] uint8[] out, out int out_len, uint8[] in);
+            public void encrypt_update (uint8[] out, out int out_len, uint8[] in) throws GLib.Error {
+                throw_if_error (encrypt_update_ (@out, out out_len, in));
+            }
+            [CCode (cname = "EVP_EncryptFinal")]
+            private int encrypt_final_ ([CCode (array_length = false)] uchar[] out, out int out_len);
+            public void encrypt_final (uint8[] out, out int out_len) throws GLib.Error {
+                throw_if_error (encrypt_final_ (@out, out out_len));
+            }
+
+            [CCode (cname = "EVP_DecryptInit")]
+            private int decrypt_init_ (Cipher? cipher, [CCode (array_length = false)] uint8[]? key, [CCode (array_length = false)] uint8[]? iv);
+            public void decrypt_init (Cipher? cipher, uint8[]? key, uint8[]? iv) throws GLib.Error {
+                throw_if_error (decrypt_init_ (cipher, key, iv));
+            }
+            [CCode (cname = "EVP_DecryptUpdate")]
+            private int decrypt_update_ ([CCode (array_length = false)] uchar[] out, out int out_len, uint8[] in);
+            public void decrypt_update (uint8[] out, out int out_len, uint8[] in) throws GLib.Error {
+                throw_if_error (decrypt_update_ (@out, out out_len, in));
+            }
+            [CCode (cname = "EVP_DecryptFinal")]
+            private int decrypt_final_ ([CCode (array_length = false)] uchar[] out, out int out_len);
+            public void decrypt_final (uint8[] out, out int out_len) throws GLib.Error {
+                throw_if_error (decrypt_final_ (@out, out out_len));
+            }
+
+            public int reset();
+            public int set_key_length (int keylen);
+            public int set_padding (int pad);
+        }
+
+        [CCode (cname = "int", cprefix = "EVP_CTRL_", has_type_id = false)]
+        public enum Control {
+            INIT,
+            SET_KEY_LENGTH,
+            GET_RC2_KEY_BITS,
+            SET_RC2_KEY_BITS,
+            GET_RC5_ROUNDS,
+            SET_RC5_ROUNDS,
+            RAND_KEY,
+            PBE_PRF_NID,
+            COPY,
+            AEAD_SET_IVLEN,
+            AEAD_GET_TAG,
+            AEAD_SET_TAG,
+            AEAD_SET_IV_FIXED,
+            GCM_SET_IVLEN,
+            GCM_GET_TAG,
+            GCM_SET_TAG,
+            GCM_SET_IV_FIXED,
+            GCM_IV_GEN,
+            CCM_SET_IVLEN,
+            CCM_GET_TAG,
+            CCM_SET_TAG,
+            CCM_SET_IV_FIXED,
+            CCM_SET_L,
+            CCM_SET_MSGLEN,
+            AEAD_TLS1_AAD,
+            AEAD_SET_MAC_KEY,
+            GCM_SET_IV_INV,
+            TLS1_1_MULTIBLOCK_AAD,
+            TLS1_1_MULTIBLOCK_ENCRYPT,
+            TLS1_1_MULTIBLOCK_DECRYPT,
+            TLS1_1_MULTIBLOCK_MAX_BUFSIZE,
+            SSL3_MASTER_SECRET,
+            SET_SBOX,
+            SBOX_USED,
+            KEY_MESH,
+            BLOCK_PADDING_MODE,
+            SET_PIPELINE_OUTPUT_BUFS,
+            SET_PIPELINE_INPUT_BUFS,
+            SET_PIPELINE_INPUT_LENS,
+            GET_IVLEN,
+        }
+
+        public static unowned Cipher? aes_128_gcm ();
+        public static unowned Cipher? aes_256_gcm ();
+
+        public static unowned MessageDigest sha256 ();
+    }
+
+    [CCode (lower_case_cprefix = "RAND_", cprefix = "RAND_", cheader_filename = "openssl/rand.h")]
+    namespace RAND {
+        public static int bytes (uint8[] buf);
+        public static int priv_bytes (uint8[] buf);
+    }
+
+    [Compact]
+    [CCode (cname = "SSL", lower_case_cprefix = "SSL_", cprefix = "SSL_", ref_function = "SSL_up_ref", ref_function_void = true, unref_function = "SSL_free", cheader_filename = "openssl/ssl.h")]
+    class SSL {
+        [Compact]
+        [CCode (cname = "SSL_CTX", lower_case_cprefix = "SSL_CTX_", cprefix = "SSL_CTX_", ref_function = "SSL_CTX_up_ref", ref_function_void = true, unref_function = "SSL_CTX_free")]
+        public class Context {
+            public Context (Method method);
+            public int set_tlsext_use_srtp (string profiles);
+            public int use_certificate (X509.Certificate certificate);
+            [CCode (cname = "SSL_CTX_use_PrivateKey")]
+            public int use_private_key (EVP.Key private_key);
+        }
+
+        [CCode (cname = "const SSL_METHOD*")]
+        public enum Method {
+            [CCode (cname = "DTLS_client_method()")]
+            DTLS_CLIENT,
+            [CCode (cname = "DTLS_server_method()")]
+            DTLS_SERVER,
+        }
+
+        [CCode (cname = "int", has_type_id = false)]
+        public enum Error {
+            NONE,
+            ZERO_RETURN,
+            WANT_READ,
+            WANT_WRITE,
+            WANT_CONNECT,
+            WANT_ACCEPT,
+            WANT_X509_LOOKUP,
+            WANT_ASYNC,
+            WANT_ASYNC_JOB,
+            WANT_CLIENT_HELLO_CB,
+            SYSCALL,
+            SSL
+        }
+
+        public SSL (Context context);
+        public BIO rbio { get; [CCode (cname="SSL_set0_rbio")] owned set; }
+        public BIO wbio { get; [CCode (cname="SSL_set0_wbio")] owned set; }
+
+        [CCode (cname = "SSL_do_handshake")]
+        private int do_handshake_ ();
+        [CCode (cname = "SSL_do_handshake_")]
+        public Error do_handshake () throws GLib.Error {
+            int ret = throw_if_error (do_handshake_ ());
+            return get_error (ret);
+        }
+        [CCode (cname = "SSL_export_keying_material")]
+        private int export_keying_material_ (uint8[] out, string label, size_t llen, [CCode (type = "const unsigned char *")] string context, size_t contextlen, bool use_context);
+        [CCode (cname = "SSL_export_keying_material_")]
+        public void export_keying_material (uint8[] out, string label, string? context = null) throws GLib.Error {
+            throw_if_error (export_keying_material_ (@out, label, label.length, context, context == null ? 0 : context.length, context != null));
+        }
+        public Error get_error (int ret);
+        public void set_accept_state ();
+        public void set_connect_state ();
+        public int want ();
+    }
+
+    [CCode (cprefix = "X509_", lower_case_cprefix = "X509_", cheader_filename = "openssl/x509.h")]
+    namespace X509 {
+        [Compact]
+        [CCode (cname = "X509", lower_case_cprefix = "X509_", cprefix = "X509_", ref_function = "X509_up_ref", ref_function_void = true, unref_function = "X509_free")]
+        public class Certificate {
+            public Certificate ();
+            public ASN1.Time not_before {
+                [CCode (cname = "X509_get_notBefore")]
+                get;
+                [CCode (cname = "X509_set_notBefore")]
+                set;
+            }
+            public ASN1.Time not_after {
+                [CCode (cname = "X509_get_notAfter")]
+                get;
+                [CCode (cname = "X509_set_notAfter")]
+                set;
+            }
+            public ASN1.Integer serial_number {
+                [CCode (cname = "X509_get_serialNumber")]
+                get;
+                [CCode (cname = "X509_set_serialNumber")]
+                set;
+            }
+            [CCode (cname = "X509_digest")]
+            private int digest_ (EVP.MessageDigest type, uchar* md, ref uint len);
+            [CCode (cname = "X509_digest_")]
+            public uint8[] digest (EVP.MessageDigest type, size_t buf_len = 512) throws GLib.Error {
+                uint8[] buf = new uint8[buf_len];
+                uint buf_out_size = (uint) buf_len;
+                throw_if_error (digest_ (type, (uchar*) buf, ref buf_out_size));
+
+                uint8[] ret = new uint8[buf_out_size];
+                for (int i = 0; i < buf_out_size; i++) {
+                    ret[i] = buf[i];
+                }
+                return ret;
+            }
+            [CCode (cname = "X509_set_pubkey")]
+            public int set_public_key (EVP.Key public_key);
+            public int set_version (long version);
+            [CCode (cname = "X509_sign")]
+            private int sign_ (EVP.Key private_key, EVP.MessageDigest md);
+            [CCode (cname = "X509_sign_")]
+            public void sign (EVP.Key private_key, EVP.MessageDigest md) throws GLib.Error {
+                throw_if_error (sign_ (private_key, md));
+            }
+        }
+    }
+
+    public int throw_if_error(int res) throws GLib.Error {
+        if (res <= 0) {
+            ulong error = ERR.get_error ();
+            if (error == 0) return res;
+            throw new GLib.Error (-1, (int) error, "%s:%s", ERR.lib_error_string (error), ERR.reason_error_string (error));
+        }
+        return res;
+    }
+}
\ No newline at end of file
diff --git a/meson.build b/meson.build
index df5a2b80..84597fd4 100644
--- a/meson.build
+++ b/meson.build
@@ -47,9 +47,6 @@ vala_c_args = cc.get_supported_arguments([
     '-Wno-unused-variable',
 ])
 
-# plugin_crypto is enabled if any of the crypto plugins is enabled, auto if
-# none of them are explicitly enabled but at least one is set to auto, or
-# disabled if all of them are disabled.
 plugin_crypto = get_option('plugin-ice')
 foreach plugin : ['plugin-ice', 'plugin-omemo', 'plugin-rtp']
     if get_option(plugin).enabled() and not plugin_crypto.enabled()
@@ -59,11 +56,30 @@ foreach plugin : ['plugin-ice', 'plugin-omemo', 'plugin-rtp']
     endif
 endforeach
 
+if get_option('crypto-backend') == 'auto'
+    # Prefer libgcrypt/gnutls over openssl because glib-networking is usually
+    # built with gnutls anyway.
+    dep_libgcrypt = dependency('libgcrypt', required: false)
+    dep_gnutls = dependency('gnutls', required: false)
+    if dep_libgcrypt.found() and dep_gnutls.found()
+        crypto_backend = 'gnutls'
+    else
+        dep_openssl = dependency('openssl', disabler: true, required: plugin_crypto)
+        crypto_backend = 'openssl'
+    endif
+elif get_option('crypto-backend') == 'openssl'
+    dep_openssl = dependency('openssl', disabler: true, required: plugin_crypto)
+    crypto_backend = 'openssl'
+elif get_option('crypto-backend') == 'gnutls'
+    dep_libgcrypt = dependency('libgcrypt', disabler: true, required: plugin_crypto)
+    dep_gnutls = dependency('gnutls', disabler: true, required: get_option('plugin-ice'))
+    crypto_backend = 'gnutls'
+endif
+
 dep_gdk_pixbuf = dependency('gdk-pixbuf-2.0')
 dep_gee = dependency('gee-0.8')
 dep_gio = dependency('gio-2.0')
 dep_glib = dependency('glib-2.0')
-dep_gnutls = dependency('gnutls', disabler: true, required: get_option('plugin-ice'))
 dep_gmodule = dependency('gmodule-2.0')
 dep_gpgme = dependency('gpgme', disabler: true, required: get_option('plugin-openpgp'))
 dep_gstreamer = dependency('gstreamer-1.0', disabler: true, required: get_option('plugin-rtp'))
@@ -75,7 +91,6 @@ dep_gtk4 = dependency('gtk4')
 dep_icu_uc = dependency('icu-uc')
 dep_libadwaita = dependency('libadwaita-1', version: '>=1.5')
 dep_libcanberra = dependency('libcanberra', disabler: true, required: get_option('plugin-notification-sound'))
-dep_libgcrypt = dependency('libgcrypt', disabler: true, required: plugin_crypto)
 dep_libqrencode = dependency('libqrencode', disabler: true, required: get_option('plugin-omemo'))
 dep_libsrtp2 = dependency('libsrtp2', disabler: true, required: plugin_crypto)
 dep_libomemo_c = dependency('libomemo-c', disabler: true, required: get_option('plugin-omemo'))
diff --git a/meson_options.txt b/meson_options.txt
index 93c1f12a..bbf7a046 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -1,6 +1,7 @@
 option('plugindir', type: 'string', value: 'dino/plugins', description: 'Dino plugin directory, relative to libdir')
 
 option('set-install-rpath', type: 'boolean', value: false, description: 'Set rpath of installed binaries to the configured libdir')
+option('crypto-backend', type: 'combo', choices: ['auto', 'openssl', 'gnutls'], value: 'auto', description: 'Preferred crypto backend')
 
 option('plugin-ice', type: 'feature', value: 'enabled', description: 'Peer-to-peer communication')
 option('plugin-omemo', type: 'feature', value: 'enabled', description: 'End-to-end encryption using OMEMO')
diff --git a/plugins/ice/meson.build b/plugins/ice/meson.build
index 1cec8b38..5ed807bf 100644
--- a/plugins/ice/meson.build
+++ b/plugins/ice/meson.build
@@ -5,7 +5,6 @@ dependencies = [
     dep_gio,
     dep_glib,
     dep_gmodule,
-    dep_gnutls,
     dep_nice,
     dep_qlite,
     dep_xmpp_vala,
@@ -24,6 +23,18 @@ c_args = vala_c_args + [
 vala_args = [
     '--vapidir', meson.current_source_dir() / 'vapi',
 ]
-lib_ice = shared_library('ice', sources, name_prefix: '', c_args: c_args, vala_args: vala_args, dependencies: dependencies, install: true, install_dir: get_option('libdir') / get_option('plugindir'), install_rpath: default_install_rpath)
+if crypto_backend == 'gnutls'
+    dependencies += [ dep_gnutls ]
+    sources += files(
+        'src/dtls_srtp_gnutls.vala'
+    )
+else # openssl
+    dependencies += [ dep_openssl ]
+    sources += files(
+        'src/dtls_srtp_openssl.vala',
+        'src/openssl_utils.c',
+    )
+endif
+lib_ice = shared_library('ice', sources, name_prefix: '', c_args: c_args, vala_args: vala_args, include_directories: include_directories('src'), dependencies: dependencies, install: true, install_dir: get_option('libdir') / get_option('plugindir'), install_rpath: default_install_rpath)
 dep_ice = declare_dependency(link_with: lib_ice, include_directories: include_directories('.'))
 summary('Peer-to-peer communication (ice)', dep_ice.found(), bool_yn: true, section: 'Plugins')
diff --git a/plugins/ice/src/dtls_srtp.vala b/plugins/ice/src/dtls_srtp.vala
index c9813b7e..41918359 100644
--- a/plugins/ice/src/dtls_srtp.vala
+++ b/plugins/ice/src/dtls_srtp.vala
@@ -1,14 +1,10 @@
-using GnuTLS;
-
 namespace Dino.Plugins.Ice.DtlsSrtp {
 
-public class CredentialsCapsule {
+public abstract class CredentialsCapsule : Object {
     public uint8[] own_fingerprint;
-    public X509.Certificate[] own_cert;
-    public X509.PrivateKey private_key;
 }
 
-public class Handler {
+public abstract class AbstractHandler {
 
     public signal void send_data(uint8[] data);
 
@@ -21,18 +17,18 @@ public class Handler {
     public uint8[] peer_fingerprint { get; set; }
     public string peer_fp_algo { get; set; }
 
-    private CredentialsCapsule credentials;
-    private Cond buffer_cond = Cond();
-    private Mutex buffer_mutex = Mutex();
-    private Gee.LinkedList<Bytes> buffer_queue = new Gee.LinkedList<Bytes>();
+    protected CredentialsCapsule credentials;
+    protected Cond buffer_cond = Cond();
+    protected Mutex buffer_mutex = Mutex();
+    protected Gee.LinkedList<Bytes> buffer_queue = new Gee.LinkedList<Bytes>();
 
-    private bool running = false;
-    private bool stop = false;
-    private bool restart = false;
+    protected bool running = false;
+    protected bool stop = false;
+    protected bool restart = false;
 
-    private Crypto.Srtp.Session srtp_session = new Crypto.Srtp.Session();
+    protected Crypto.Srtp.Session srtp_session = new Crypto.Srtp.Session();
 
-    public Handler.with_cert(CredentialsCapsule creds) {
+    protected AbstractHandler.with_cert(CredentialsCapsule creds) {
         this.credentials = creds;
         this.own_fingerprint = creds.own_fingerprint;
     }
@@ -79,38 +75,6 @@ public class Handler {
         buffer_mutex.unlock();
     }
 
-    internal static CredentialsCapsule generate_credentials() throws GLib.Error {
-        int err = 0;
-
-        X509.PrivateKey private_key = X509.PrivateKey.create();
-        err = private_key.generate(PKAlgorithm.ECDSA, 256);
-        throw_if_error(err);
-
-        var start_time = new DateTime.now_local().add_days(-1);
-        var end_time = start_time.add_days(2);
-
-        X509.Certificate cert = X509.Certificate.create();
-        cert.set_key(private_key);
-        cert.set_version(1);
-        cert.set_activation_time ((time_t) start_time.to_unix ());
-        cert.set_expiration_time ((time_t) end_time.to_unix ());
-
-        uint32 serial = 1;
-        cert.set_serial(&serial, sizeof(uint32));
-
-        cert.sign(cert, private_key);
-
-        uint8[] own_fingerprint = get_fingerprint(cert, DigestAlgorithm.SHA256);
-        X509.Certificate[] own_cert = new X509.Certificate[] { (owned)cert };
-
-        var creds = new CredentialsCapsule();
-        creds.own_fingerprint = own_fingerprint;
-        creds.own_cert = (owned) own_cert;
-        creds.private_key = (owned) private_key;
-
-        return creds;
-    }
-
     public void stop_dtls_connection() {
         buffer_mutex.lock();
         stop = true;
@@ -118,228 +82,49 @@ public class Handler {
         buffer_mutex.unlock();
     }
 
-    public async Xmpp.Xep.Jingle.ContentEncryption? setup_dtls_connection() {
-        MainContext context = MainContext.current_source().get_context();
-        var thread = new Thread<Xmpp.Xep.Jingle.ContentEncryption>("dtls-connection", () => {
-            var res = setup_dtls_connection_thread();
-            Source source = new IdleSource();
-            source.set_callback(setup_dtls_connection.callback);
-            source.attach(context);
-            return res;
-        });
-        yield;
-        return thread.join();
-    }
-
-    private Xmpp.Xep.Jingle.ContentEncryption? setup_dtls_connection_thread() {
+    protected Bytes get_buffer_if_present () {
         buffer_mutex.lock();
-        if (stop) {
-            restart = true;
+        if (buffer_queue.size == 0) {
             buffer_mutex.unlock();
             return null;
         }
-        if (running || ready) {
-            buffer_mutex.unlock();
-            return null;
-        }
-        running = true;
-        restart = false;
-        buffer_mutex.unlock();
-
-        InitFlags server_or_client = mode == Mode.SERVER ? InitFlags.SERVER : InitFlags.CLIENT;
-        debug("Setting up DTLS connection. We're %s", mode.to_string());
-
-        CertificateCredentials cert_cred = CertificateCredentials.create();
-        int err = cert_cred.set_x509_key(credentials.own_cert, credentials.private_key);
-        throw_if_error(err);
-
-        Session? session = Session.create(server_or_client | InitFlags.DATAGRAM);
-        session.enable_heartbeat(1);
-        session.set_srtp_profile_direct("SRTP_AES128_CM_HMAC_SHA1_80");
-        session.set_credentials(GnuTLS.CredentialsType.CERTIFICATE, cert_cred);
-        session.server_set_request(CertificateRequest.REQUEST);
-        session.set_priority_from_string("NORMAL:!VERS-TLS-ALL:+VERS-DTLS-ALL:+CTYPE-CLI-X509");
-
-        session.set_transport_pointer(this);
-        session.set_pull_function(pull_function);
-        session.set_pull_timeout_function(pull_timeout_function);
-        session.set_push_function(push_function);
-        session.set_verify_function(verify_function);
-
-        DateTime maximum_time = new DateTime.now_utc().add_seconds(20);
-        do {
-            err = session.handshake();
-
-            DateTime current_time = new DateTime.now_utc();
-            if (maximum_time.compare(current_time) < 0) {
-                warning("DTLS handshake timeouted");
-                err = ErrorCode.APPLICATION_ERROR_MIN + 1;
-                break;
-            }
-            if (stop) {
-                debug("DTLS handshake stopped");
-                err = ErrorCode.APPLICATION_ERROR_MIN + 2;
-                break;
-            }
-        } while (err < 0 && !((ErrorCode)err).is_fatal());
-
-        buffer_mutex.lock();
-        if (stop) {
-            stop = false;
-            running = false;
-            bool restart = restart;
-            buffer_mutex.unlock();
-            if (restart) {
-                debug("Restarting DTLS handshake");
-                return setup_dtls_connection_thread();
-            }
-            return null;
-        }
+        Bytes res = buffer_queue.remove_at(0);
         buffer_mutex.unlock();
-        if (err != ErrorCode.SUCCESS) {
-            warning("DTLS handshake failed: %s", ((ErrorCode)err).to_string());
-            return null;
-        }
-
-        uint8[] km = new uint8[150];
-        Datum? client_key, client_salt, server_key, server_salt;
-        session.get_srtp_keys(km, km.length, out client_key, out client_salt, out server_key, out server_salt);
-        if (client_key == null || client_salt == null || server_key == null || server_salt == null) {
-            warning("SRTP client/server key/salt null");
-        }
-
-        debug("Finished DTLS connection. We're %s", mode.to_string());
-        if (mode == Mode.SERVER) {
-            srtp_session.set_encryption_key(Crypto.Srtp.AES_CM_128_HMAC_SHA1_80, server_key.extract(), server_salt.extract());
-            srtp_session.set_decryption_key(Crypto.Srtp.AES_CM_128_HMAC_SHA1_80, client_key.extract(), client_salt.extract());
-        } else {
-            srtp_session.set_encryption_key(Crypto.Srtp.AES_CM_128_HMAC_SHA1_80, client_key.extract(), client_salt.extract());
-            srtp_session.set_decryption_key(Crypto.Srtp.AES_CM_128_HMAC_SHA1_80, server_key.extract(), server_salt.extract());
-        }
-        return new Xmpp.Xep.Jingle.ContentEncryption(Xmpp.Xep.JingleIceUdp.DTLS_NS_URI, "DTLS-SRTP", credentials.own_fingerprint, peer_fingerprint);
+        return res;
     }
 
-    private static ssize_t pull_function(void* transport_ptr, uint8[] buffer) {
-        Handler self = transport_ptr as Handler;
-
-        self.buffer_mutex.lock();
-        while (self.buffer_queue.size == 0) {
-            self.buffer_cond.wait(self.buffer_mutex);
-            if (self.stop) {
-                self.buffer_mutex.unlock();
-                debug("DTLS handshake pull_function stopped");
-                return -1;
-            }
-        }
-        Bytes data = self.buffer_queue.remove_at(0);
-        self.buffer_mutex.unlock();
-
-        uint8[] data_uint8 = Bytes.unref_to_data((owned) data);
-        Memory.copy(buffer, data_uint8, data_uint8.length);
-
-        // The callback should return 0 on connection termination, a positive number indicating the number of bytes received, and -1 on error.
-        return (ssize_t)data_uint8.length;
-    }
-
-    private static int pull_timeout_function(void* transport_ptr, uint ms) {
-        Handler self = transport_ptr as Handler;
-
-        int64 end_time = get_monotonic_time() + ms * 1000;
-
-        self.buffer_mutex.lock();
-        while (self.buffer_queue.size == 0) {
-            self.buffer_cond.wait_until(self.buffer_mutex, end_time);
-            if (self.stop) {
-                self.buffer_mutex.unlock();
-                debug("DTLS handshake pull_timeout_function stopped");
-                return -1;
-            }
-
-            if (get_monotonic_time() > end_time) {
-                self.buffer_mutex.unlock();
-                return 0;
+    public async Xmpp.Xep.Jingle.ContentEncryption? setup_dtls_connection() {
+        MainContext context = MainContext.current_source().get_context();
+        var thread = new Thread<Xmpp.Xep.Jingle.ContentEncryption>("dtls-connection", () => {
+            // Check we can start working on the thread
+            buffer_mutex.lock();
+            if (stop) {
+                restart = true;
+                buffer_mutex.unlock();
+                return null;
             }
-        }
-        self.buffer_mutex.unlock();
-
-        // The callback should return 0 on timeout, a positive number if data can be received, and -1 on error.
-        return 1;
-    }
-
-    private static ssize_t push_function(void* transport_ptr, uint8[] buffer) {
-        Handler self = transport_ptr as Handler;
-        self.send_data(buffer);
-
-        // The callback should return a positive number indicating the bytes sent, and -1 on error.
-        return (ssize_t)buffer.length;
-    }
-
-    private static int verify_function(Session session) {
-        Handler self = session.get_transport_pointer() as Handler;
-        try {
-            bool valid = self.verify_peer_cert(session);
-            if (!valid) {
-                warning("DTLS certificate invalid. Aborting handshake.");
-                return 1;
+            if (running || ready) {
+                buffer_mutex.unlock();
+                return null;
             }
-        } catch (Error e) {
-            warning("Error during DTLS certificate validation: %s. Aborting handshake.", e.message);
-            return 1;
-        }
-
-        // The callback function should return 0 for the handshake to continue or non-zero to terminate.
-        return 0;
-    }
-
-    private bool verify_peer_cert(Session session) throws GLib.Error {
-        unowned Datum[] cert_datums = session.get_peer_certificates();
-        if (cert_datums.length == 0) {
-            warning("No peer certs");
-            return false;
-        }
-        if (cert_datums.length > 1) warning("More than one peer cert");
-
-        X509.Certificate peer_cert = X509.Certificate.create();
-        peer_cert.import(ref cert_datums[0], CertificateFormat.DER);
-
-        DigestAlgorithm algo;
-        switch (peer_fp_algo) {
-            case "sha-256":
-                algo = DigestAlgorithm.SHA256;
-                break;
-            default:
-                warning("Unkown peer fingerprint algorithm: %s", peer_fp_algo);
-                return false;
-        }
-
-        uint8[] real_peer_fp = get_fingerprint(peer_cert, algo);
-
-        if (real_peer_fp.length != this.peer_fingerprint.length) {
-            warning("Fingerprint lengths not equal %i vs %i", real_peer_fp.length, peer_fingerprint.length);
-            return false;
-        }
+            running = true;
+            restart = false;
+            buffer_mutex.unlock();
 
-        for (int i = 0; i < real_peer_fp.length; i++) {
-            if (real_peer_fp[i] != this.peer_fingerprint[i]) {
-                warning("First cert in peer cert list doesn't equal advertised one: %s vs %s", format_fingerprint(real_peer_fp), format_fingerprint(peer_fingerprint));
-                return false;
-            }
-        }
+            // Actual work
+            var res = setup_dtls_connection_thread();
 
-        return true;
+            // Callback
+            Source source = new IdleSource();
+            source.set_callback(setup_dtls_connection.callback);
+            source.attach(context);
+            return res;
+        });
+        yield;
+        return thread.join();
     }
-}
-
-private uint8[] get_fingerprint(X509.Certificate certificate, DigestAlgorithm digest_algo) {
-    uint8[] buf = new uint8[512];
-    size_t buf_out_size = 512;
-    certificate.get_fingerprint(digest_algo, buf, ref buf_out_size);
 
-    uint8[] ret = new uint8[buf_out_size];
-    for (int i = 0; i < buf_out_size; i++) {
-        ret[i] = buf[i];
-    }
-    return ret;
+    protected abstract Xmpp.Xep.Jingle.ContentEncryption? setup_dtls_connection_thread();
 }
 
 private string format_fingerprint(uint8[] fingerprint) {
diff --git a/plugins/ice/src/dtls_srtp_gnutls.vala b/plugins/ice/src/dtls_srtp_gnutls.vala
new file mode 100644
index 00000000..91a7cfb2
--- /dev/null
+++ b/plugins/ice/src/dtls_srtp_gnutls.vala
@@ -0,0 +1,245 @@
+using GnuTLS;
+
+namespace Dino.Plugins.Ice.DtlsSrtp {
+
+public class CredentialsCapsuleGnuTLS : CredentialsCapsule {
+    public X509.Certificate[] own_cert;
+    public X509.PrivateKey private_key;
+}
+
+private uint8[] get_fingerprint(X509.Certificate certificate, DigestAlgorithm digest_algo) {
+    uint8[] buf = new uint8[512];
+    size_t buf_out_size = 512;
+    certificate.get_fingerprint(digest_algo, buf, ref buf_out_size);
+
+    uint8[] ret = new uint8[buf_out_size];
+    for (int i = 0; i < buf_out_size; i++) {
+        ret[i] = buf[i];
+    }
+    return ret;
+}
+
+internal CredentialsCapsule generate_credentials () throws GLib.Error {
+    int err = 0;
+
+    X509.PrivateKey private_key = X509.PrivateKey.create ();
+    err = private_key.generate (PKAlgorithm.ECDSA, 256);
+    throw_if_error (err);
+
+    var start_time = new DateTime.now_local().add_days(-1);
+    var end_time = start_time.add_days (2);
+
+    X509.Certificate cert = X509.Certificate.create ();
+    cert.set_key (private_key);
+    cert.set_version (1);
+    cert.set_activation_time ((time_t) start_time.to_unix ());
+    cert.set_expiration_time ((time_t) end_time.to_unix ());
+
+    uint32 serial = 1;
+    cert.set_serial (&serial, sizeof(uint32));
+
+    cert.sign (cert, private_key);
+
+    uint8[] own_fingerprint = get_fingerprint (cert, DigestAlgorithm.SHA256);
+    X509.Certificate[] own_cert = new X509.Certificate[] { (owned)cert };
+
+    var creds = new CredentialsCapsuleGnuTLS();
+    creds.own_fingerprint = own_fingerprint;
+    creds.own_cert = (owned) own_cert;
+    creds.private_key = (owned) private_key;
+
+    return creds;
+}
+
+public class Handler : AbstractHandler {
+
+    public Handler.with_cert(CredentialsCapsule creds) {
+        base.with_cert(creds);
+    }
+
+    protected override Xmpp.Xep.Jingle.ContentEncryption? setup_dtls_connection_thread() {
+        InitFlags server_or_client = mode == Mode.SERVER ? InitFlags.SERVER : InitFlags.CLIENT;
+        debug("Setting up DTLS connection using GnuTLS. We're %s", mode.to_string());
+
+        CertificateCredentials cert_cred = CertificateCredentials.create();
+        int err = cert_cred.set_x509_key(((CredentialsCapsuleGnuTLS)credentials).own_cert, ((CredentialsCapsuleGnuTLS)credentials).private_key);
+        throw_if_error(err);
+
+        Session? session = Session.create(server_or_client | InitFlags.DATAGRAM);
+        session.enable_heartbeat(1);
+        session.set_srtp_profile_direct("SRTP_AES128_CM_HMAC_SHA1_80");
+        session.set_credentials(GnuTLS.CredentialsType.CERTIFICATE, cert_cred);
+        session.server_set_request(CertificateRequest.REQUEST);
+        session.set_priority_from_string("NORMAL:!VERS-TLS-ALL:+VERS-DTLS-ALL:+CTYPE-CLI-X509");
+
+        session.set_transport_pointer(this);
+        session.set_pull_function(pull_function);
+        session.set_pull_timeout_function(pull_timeout_function);
+        session.set_push_function(push_function);
+        session.set_verify_function(verify_function);
+
+        DateTime maximum_time = new DateTime.now_utc().add_seconds(20);
+        do {
+            err = session.handshake();
+
+            DateTime current_time = new DateTime.now_utc();
+            if (maximum_time.compare(current_time) < 0) {
+                warning("DTLS handshake timeouted");
+                err = ErrorCode.APPLICATION_ERROR_MIN + 1;
+                break;
+            }
+            if (stop) {
+                debug("DTLS handshake stopped");
+                err = ErrorCode.APPLICATION_ERROR_MIN + 2;
+                break;
+            }
+        } while (err < 0 && !((ErrorCode)err).is_fatal());
+
+        buffer_mutex.lock();
+        if (stop) {
+            stop = false;
+            running = false;
+            bool restart = restart;
+            buffer_mutex.unlock();
+            if (restart) {
+                debug("Restarting DTLS handshake");
+                return setup_dtls_connection_thread();
+            }
+            return null;
+        }
+        buffer_mutex.unlock();
+        if (err != ErrorCode.SUCCESS) {
+            warning("DTLS handshake failed: %s", ((ErrorCode)err).to_string());
+            return null;
+        }
+
+        uint8[] km = new uint8[150];
+        Datum? client_key, client_salt, server_key, server_salt;
+        session.get_srtp_keys(km, km.length, out client_key, out client_salt, out server_key, out server_salt);
+        if (client_key == null || client_salt == null || server_key == null || server_salt == null) {
+            warning("SRTP client/server key/salt null");
+        }
+
+        debug("Finished DTLS connection. We're %s", mode.to_string());
+        if (mode == Mode.SERVER) {
+            srtp_session.set_encryption_key(Crypto.Srtp.AES_CM_128_HMAC_SHA1_80, server_key.extract(), server_salt.extract());
+            srtp_session.set_decryption_key(Crypto.Srtp.AES_CM_128_HMAC_SHA1_80, client_key.extract(), client_salt.extract());
+        } else {
+            srtp_session.set_encryption_key(Crypto.Srtp.AES_CM_128_HMAC_SHA1_80, client_key.extract(), client_salt.extract());
+            srtp_session.set_decryption_key(Crypto.Srtp.AES_CM_128_HMAC_SHA1_80, server_key.extract(), server_salt.extract());
+        }
+        return new Xmpp.Xep.Jingle.ContentEncryption(Xmpp.Xep.JingleIceUdp.DTLS_NS_URI, "DTLS-SRTP", credentials.own_fingerprint, peer_fingerprint);
+    }
+
+    private static ssize_t pull_function(void* transport_ptr, uint8[] buffer) {
+        Handler self = transport_ptr as Handler;
+
+        self.buffer_mutex.lock();
+        while (self.buffer_queue.size == 0) {
+            self.buffer_cond.wait(self.buffer_mutex);
+            if (self.stop) {
+                self.buffer_mutex.unlock();
+                debug("DTLS handshake pull_function stopped");
+                return -1;
+            }
+        }
+        Bytes data = self.buffer_queue.remove_at(0);
+        self.buffer_mutex.unlock();
+
+        uint8[] data_uint8 = Bytes.unref_to_data((owned) data);
+        Memory.copy(buffer, data_uint8, data_uint8.length);
+
+        // The callback should return 0 on connection termination, a positive number indicating the number of bytes received, and -1 on error.
+        return (ssize_t)data_uint8.length;
+    }
+
+    private static int pull_timeout_function(void* transport_ptr, uint ms) {
+        Handler self = transport_ptr as Handler;
+
+        int64 end_time = get_monotonic_time() + ms * 1000;
+
+        self.buffer_mutex.lock();
+        while (self.buffer_queue.size == 0) {
+            self.buffer_cond.wait_until(self.buffer_mutex, end_time);
+            if (self.stop) {
+                self.buffer_mutex.unlock();
+                debug("DTLS handshake pull_timeout_function stopped");
+                return -1;
+            }
+
+            if (get_monotonic_time() > end_time) {
+                self.buffer_mutex.unlock();
+                return 0;
+            }
+        }
+        self.buffer_mutex.unlock();
+
+        // The callback should return 0 on timeout, a positive number if data can be received, and -1 on error.
+        return 1;
+    }
+
+    private static ssize_t push_function(void* transport_ptr, uint8[] buffer) {
+        Handler self = transport_ptr as Handler;
+        self.send_data(buffer);
+
+        // The callback should return a positive number indicating the bytes sent, and -1 on error.
+        return (ssize_t)buffer.length;
+    }
+
+    private static int verify_function(Session session) {
+        Handler self = session.get_transport_pointer() as Handler;
+        try {
+            bool valid = self.verify_peer_cert(session);
+            if (!valid) {
+                warning("DTLS certificate invalid. Aborting handshake.");
+                return 1;
+            }
+        } catch (Error e) {
+            warning("Error during DTLS certificate validation: %s. Aborting handshake.", e.message);
+            return 1;
+        }
+
+        // The callback function should return 0 for the handshake to continue or non-zero to terminate.
+        return 0;
+    }
+
+    private bool verify_peer_cert(Session session) throws GLib.Error {
+        unowned Datum[] cert_datums = session.get_peer_certificates();
+        if (cert_datums.length == 0) {
+            warning("No peer certs");
+            return false;
+        }
+        if (cert_datums.length > 1) warning("More than one peer cert");
+
+        X509.Certificate peer_cert = X509.Certificate.create();
+        peer_cert.import(ref cert_datums[0], CertificateFormat.DER);
+
+        DigestAlgorithm algo;
+        switch (peer_fp_algo) {
+            case "sha-256":
+                algo = DigestAlgorithm.SHA256;
+                break;
+            default:
+                warning("Unkown peer fingerprint algorithm: %s", peer_fp_algo);
+                return false;
+        }
+
+        uint8[] real_peer_fp = get_fingerprint(peer_cert, algo);
+
+        if (real_peer_fp.length != this.peer_fingerprint.length) {
+            warning("Fingerprint lengths not equal %i vs %i", real_peer_fp.length, peer_fingerprint.length);
+            return false;
+        }
+
+        for (int i = 0; i < real_peer_fp.length; i++) {
+            if (real_peer_fp[i] != this.peer_fingerprint[i]) {
+                warning("First cert in peer cert list doesn't equal advertised one: %s vs %s", format_fingerprint(real_peer_fp), format_fingerprint(peer_fingerprint));
+                return false;
+            }
+        }
+
+        return true;
+    }
+}
+
+}
\ No newline at end of file
diff --git a/plugins/ice/src/dtls_srtp_openssl.vala b/plugins/ice/src/dtls_srtp_openssl.vala
new file mode 100644
index 00000000..86f080e5
--- /dev/null
+++ b/plugins/ice/src/dtls_srtp_openssl.vala
@@ -0,0 +1,202 @@
+using OpenSSL;
+
+namespace Dino.Plugins.Ice.DtlsSrtp {
+
+public class CredentialsCapsuleOpenSSL : CredentialsCapsule {
+    public X509.Certificate own_cert;
+    public EVP.Key private_key;
+}
+
+internal CredentialsCapsule generate_credentials () throws GLib.Error {
+    EVP.Key key = new EVP.Key.generate_ecdsa ("prime256v1");
+
+    var start_time = new DateTime.now_local().add_days(-1);
+    var end_time = start_time.add_days (2);
+
+    X509.Certificate cert = new X509.Certificate ();
+    cert.set_public_key (key);
+    cert.set_version (1);
+    cert.not_before.set ((time_t) start_time.to_unix ());
+    cert.not_after.set ((time_t) end_time.to_unix ());
+    cert.serial_number.set (1);
+
+    cert.sign (key, EVP.sha256 ());
+
+    CredentialsCapsuleOpenSSL credentials = new CredentialsCapsuleOpenSSL ();
+    credentials.own_fingerprint = cert.digest (EVP.sha256 ());
+    credentials.own_cert = (owned) cert;
+    credentials.private_key = (owned) key;
+    return credentials;
+}
+
+public class Handler : AbstractHandler {
+
+    public Handler.with_cert (CredentialsCapsule creds) {
+        base.with_cert (creds);
+    }
+
+    protected override Xmpp.Xep.Jingle.ContentEncryption? setup_dtls_connection_thread () {
+        debug("Setting up DTLS connection using OpenSSL. We're %s", mode.to_string());
+        SSL.Context context = new SSL.Context (mode == Mode.SERVER ? SSL.Method.DTLS_SERVER : SSL.Method.DTLS_CLIENT);
+        context.set_tlsext_use_srtp ("SRTP_AES128_CM_SHA1_80");
+        context.use_certificate (((CredentialsCapsuleOpenSSL) credentials).own_cert);
+        context.use_private_key (((CredentialsCapsuleOpenSSL) credentials).private_key);
+        SSL session = new SSL (context);
+        BIO<Handler> bio = new BIO<Handler>(get_handler_based_bio_method());
+        bio.data = this;
+        session.rbio = bio;
+        session.wbio = bio;
+
+        DateTime maximum_time = new DateTime.now_utc().add_seconds(20);
+        int err = 0;
+        if (mode == Mode.SERVER) {
+            session.set_accept_state ();
+        } else {
+            session.set_connect_state ();
+        }
+        do {
+            try {
+                SSL.Error ret = session.do_handshake();
+                switch (ret) {
+                    case SSL.Error.NONE:
+                        err = 1;
+                        break;
+                    case SSL.Error.WANT_READ:
+                        debug ("DTLS wants to read, but nothing in queue, wait for buffer");
+                        buffer_mutex.lock();
+                        if (buffer_queue.size == 0) {
+                            buffer_cond.wait_until(buffer_mutex, get_monotonic_time() + maximum_time.difference(new DateTime.now_utc()));
+                        }
+                        buffer_mutex.unlock();
+                        err = -1;
+                        break;
+                    default:
+                        warning ("DTLS Error: %s", @"$ret");
+                        err = 4;
+                        break;
+                }
+            } catch (Error e) {
+                warning ("DTLS Error: %s", e.message);
+                err = e.code;
+            }
+
+            DateTime current_time = new DateTime.now_utc();
+            if (maximum_time.compare(current_time) < 0) {
+                debug ("DTLS handshake timeouted");
+                err = 2;
+                break;
+            }
+            if (stop) {
+                debug ("DTLS handshake stopped");
+                err = 3;
+                break;
+            }
+        } while (err < 0);
+
+        buffer_mutex.lock();
+        if (stop) {
+            stop = false;
+            running = false;
+            bool restart = restart;
+            buffer_mutex.unlock();
+            if (restart) {
+                debug ("Restarting DTLS handshake");
+                return setup_dtls_connection_thread();
+            }
+            return null;
+        }
+        buffer_mutex.unlock();
+        if (err != 1) {
+            debug ("DTLS handshake failed");
+            return null;
+        }
+
+        // TODO: Check peer certificate
+
+        uint8[] km = new uint8[60];
+        session.export_keying_material (km, "EXTRACTOR-dtls_srtp");
+        uint8[] client_key = km[0:16];
+        uint8[] server_key = km[16:32];
+        uint8[] client_salt = km[32:46];
+        uint8[] server_salt = km[46:60];
+
+        debug ("Finished DTLS connection. We're %s", mode.to_string());
+        if (mode == Mode.SERVER) {
+            srtp_session.set_encryption_key (Crypto.Srtp.AES_CM_128_HMAC_SHA1_80, server_key, server_salt);
+            srtp_session.set_decryption_key (Crypto.Srtp.AES_CM_128_HMAC_SHA1_80, client_key, client_salt);
+        } else {
+            srtp_session.set_encryption_key (Crypto.Srtp.AES_CM_128_HMAC_SHA1_80, client_key, client_salt);
+            srtp_session.set_decryption_key (Crypto.Srtp.AES_CM_128_HMAC_SHA1_80, server_key, server_salt);
+        }
+        return new Xmpp.Xep.Jingle.ContentEncryption (Xmpp.Xep.JingleIceUdp.DTLS_NS_URI, "DTLS-SRTP", credentials.own_fingerprint, peer_fingerprint);
+    }
+
+    private int read_impl (BIO<Handler> bio, uint8[] out_buf) {
+        Bytes data = get_buffer_if_present ();
+        if (data == null) {
+            if (!stop) {
+                debug ("No pending buffer in queue, but end not reached yet, set_retry_read");
+                bio.set_retry_read ();
+            }
+            return -1;
+        }
+        if (data.length > out_buf.length) {
+            warning ("Buffer in queue does not fit in out_buf");
+            return -1;
+        }
+        debug ("Read %d bytes from queue", data.length);
+
+        uint8[] data_uint8 = Bytes.unref_to_data((owned) data);
+        Memory.copy (out_buf, data_uint8, data_uint8.length);
+        bio.clear_retry_flags ();
+        return data_uint8.length;
+    }
+
+    private int write_impl (BIO<Handler> bio, uint8[] buf) {
+        debug ("Write %d bytes to network", buf.length);
+        send_data (buf);
+        return buf.length;
+    }
+
+    private long ctrl_impl (BIO<Handler> bio, BIO.ControlCommand cmd, long num, void* ptr) {
+        switch (cmd) {
+            case BIO.ControlCommand.FLUSH:
+                // Datagrams are sent out immediately
+                return 1;
+            case BIO.ControlCommand.DGRAM_SET_NEXT_TIMEOUT:
+                // Datagrams are sent out immediately
+                return 1;
+            case BIO.ControlCommand.DGRAM_GET_MTU_OVERHEAD:
+                // Just some safe estimate
+                return 70;
+            case BIO.ControlCommand.DGRAM_QUERY_MTU:
+                // Just some safe estimate
+                return 1200;
+            case BIO.ControlCommand.WPENDING:
+                // Datagrams are sent out immediately
+                return 0;
+            case BIO.ControlCommand.POP:
+            case BIO.ControlCommand.PUSH:
+                // Ignored
+                return 0;
+            default:
+                warning (@"Unimplemented ctrl cmd:$cmd, num:$num");
+                return 0;
+        }
+    }
+
+    private static BIO.Method<Handler> _handler_based_bio_method_instance = null;
+
+    private static unowned BIO.Method<Handler> get_handler_based_bio_method () {
+        if (_handler_based_bio_method_instance != null) return _handler_based_bio_method_instance;
+        _handler_based_bio_method_instance = new BIO.Method<Handler> (BIO.Type.SOURCE_SINK | BIO.Type.DGRAM, "Dino DTLS Handler BIO");
+        _handler_based_bio_method_instance.read = (bio, out_buf) => bio.data.read_impl (bio, out_buf);
+        _handler_based_bio_method_instance.write = (bio, buf) => bio.data.write_impl (bio, buf);
+        _handler_based_bio_method_instance.ctrl = (bio, cmd, num, ptr) => bio.data.ctrl_impl (bio, cmd, num, ptr);
+        return _handler_based_bio_method_instance;
+    }
+}
+
+
+
+}
\ No newline at end of file
diff --git a/plugins/ice/src/module.vala b/plugins/ice/src/module.vala
index 2645d7dc..ace62108 100644
--- a/plugins/ice/src/module.vala
+++ b/plugins/ice/src/module.vala
@@ -42,7 +42,7 @@ public class Dino.Plugins.Ice.Module : JingleIceUdp.Module {
     private DtlsSrtp.CredentialsCapsule? get_create_credentials(Jid local_full_jid, Jid peer_full_jid) {
         string from_to_id = local_full_jid.to_string() + peer_full_jid.to_string();
         try {
-            if (!cerds.has_key(from_to_id)) cerds[from_to_id] = DtlsSrtp.Handler.generate_credentials();
+            if (!cerds.has_key(from_to_id)) cerds[from_to_id] = DtlsSrtp.generate_credentials();
         } catch (Error e) {
             warning("Error creating dtls credentials: %s", e.message);
         }
diff --git a/plugins/ice/src/openssl_utils.c b/plugins/ice/src/openssl_utils.c
new file mode 100644
index 00000000..7f4bf331
--- /dev/null
+++ b/plugins/ice/src/openssl_utils.c
@@ -0,0 +1,49 @@
+#include "openssl_utils.h"
+#include <openssl/opensslv.h>
+#include <openssl/ec.h>
+
+#if defined(OPENSSL_VERSION_NUMBER) && OPENSSL_VERSION_NUMBER >= 0x30000000L
+// This is for OpenSSL 3.0.0 and newer
+
+EVP_PKEY *EVP_PKEY_new_generate_ecdsa (const char* curve) {
+    // Generate EVP_PKEY directly
+    EVP_PKEY *pkey = EVP_EC_gen (curve);
+    return pkey;
+}
+
+#else
+// This is for OpenSSL before 3.0.0 and forks of earlier OpenSSL versions like LibreSSL
+
+EVP_PKEY *EVP_PKEY_new_generate_ecdsa (const char* curve) {
+    // Get NID from curve name
+    int nid = OBJ_sn2nid (curve);
+    if (nid == NID_undef) return NULL;
+
+    // Create EC_KEY
+    EC_KEY *ec_key = EC_KEY_new_by_curve_name (nid);
+    if (!ec_key) return NULL;
+
+    // Generate key
+    if (!EC_KEY_generate_key (ec_key)) {
+        EC_KEY_free (ec_key);
+        return NULL;
+    }
+
+    // Create EVP_PKEY
+    EVP_PKEY *pkey = EVP_PKEY_new ();
+    if (!pkey) {
+        EC_KEY_free (ec_key);
+        return NULL;
+    }
+
+    // Assign EC_KEY to EVP_PKEY
+    if (!EVP_PKEY_assign_EC_KEY (pkey, ec_key)) {
+        EC_KEY_free (ec_key);
+        return NULL;
+    }
+
+    // EVP_PKEY_assign_EC_KEY takes ownership of ec_key, no need to free it explicitly
+    return pkey;
+}
+
+#endif
diff --git a/plugins/ice/src/openssl_utils.h b/plugins/ice/src/openssl_utils.h
new file mode 100644
index 00000000..bcc6f53a
--- /dev/null
+++ b/plugins/ice/src/openssl_utils.h
@@ -0,0 +1,8 @@
+#ifndef DINO_OPENSSL_UTILS_H
+#define DINO_OPENSSL_UTILS_H
+
+#include <openssl/evp.h>
+
+EVP_PKEY *EVP_PKEY_new_generate_ecdsa (const char* curve);
+
+#endif //DINO_OPENSSL_UTILS_H
\ No newline at end of file
diff --git a/plugins/ice/vapi/openssl.vapi b/plugins/ice/vapi/openssl.vapi
new file mode 100644
index 00000000..e0654869
--- /dev/null
+++ b/plugins/ice/vapi/openssl.vapi
@@ -0,0 +1,218 @@
+[CCode (cprefix = "")]
+namespace OpenSSL {
+    [CCode (cprefix = "ASN1_", lower_case_cprefix = "ASN1_", cheader_filename = "openssl/asn1.h")]
+    namespace ASN1 {
+        [Compact]
+        [CCode (cname = "ASN1_INTEGER", lower_case_cprefix = "ASN1_INTEGER_", cprefix = "ASN1_INTEGER_", free_function = "ASN1_INTEGER_free")]
+        public class Integer {
+            public bool @set (long v);
+        }
+
+        [Compact]
+        [CCode (cname = "ASN1_TIME", lower_case_cprefix = "ASN1_TIME_", cprefix = "ASN1_TIME_", copy_function = "ASN1_TIME_dup", free_function = "ASN1_STRING_free")]
+        public class Time {
+            public bool @set (time_t t);
+        }
+    }
+    [Compact]
+    [CCode (cname = "BIO", lower_case_cprefix = "BIO_", cprefix = "BIO_", ref_function = "BIO_up_ref", ref_function_void = true, unref_function = "BIO_free", cheader_filename = "openssl/bio.h", simple_generics = true)]
+    public class BIO<T> {
+        [Compact]
+        [CCode (cname = "BIO_METHOD", lower_case_cprefix = "BIO_meth_", cprefix = "BIO_meth_", unref_function = "BIO_meth_free", simple_generics = true)]
+        public class Method<T> {
+            public Method (Type type, string name);
+            [CCode (has_target = false)]
+            public delegate int WriteFunc<T> (BIO<T> bio, [CCode (type = "const char *", array_length_type = "int")] uint8[] buf);
+            [CCode (has_target = false)]
+            public delegate int ReadFunc<T> (BIO<T> bio, [CCode (type = "char *", array_length_type = "int")] uint8[] out_buf);
+            [CCode (has_target = false, simple_generics = true)]
+            public delegate long CtrlFunc<T> (BIO<T> bio, ControlCommand cmd, long num, void* ptr);
+            public WriteFunc<T> write { get; set; }
+            public ReadFunc<T> read { get; set; }
+            public CtrlFunc<T> ctrl { get; set; }
+        }
+
+        [Flags]
+        [CCode (cname = "int")]
+        public enum Type {
+            SOURCE_SINK,
+            DGRAM,
+        }
+
+        [CCode (cname = "int", cprefix = "BIO_CTRL_", has_type_id = false)]
+        public enum ControlCommand {
+            RESET,
+            EOF,
+            SET,
+            GET,
+            PUSH,
+            POP,
+            GET_CLOSE,
+            SET_CLOSE,
+            PENDING,
+            FLUSH,
+            DUP,
+            WPENDING,
+
+            DGRAM_QUERY_MTU,
+            DGRAM_GET_MTU,
+            DGRAM_SET_MTU,
+            DGRAM_SET_PEER,
+            DGRAM_SET_NEXT_TIMEOUT,
+            DGRAM_GET_PEER,
+            DGRAM_GET_FALLBACK_MTU,
+            DGRAM_SET_DONT_FRAG,
+            DGRAM_GET_MTU_OVERHEAD,
+        }
+
+        public BIO (Method<T> type);
+        public T data { get; set; }
+
+        public void clear_retry_flags ();
+        public void set_retry_read ();
+        public bool should_read ();
+    }
+
+    [CCode (cprefix = "ERR_", lower_case_cprefix = "ERR_", cheader_filename = "openssl/err.h")]
+    namespace ERR {
+        public ulong get_error ();
+        public unowned string lib_error_string (ulong error);
+        public unowned string reason_error_string (ulong error);
+    }
+
+    [CCode (cprefix = "EVP_", lower_case_cprefix = "EVP_", cheader_filename = "openssl/evp.h")]
+    namespace EVP {
+        [Compact]
+        [CCode (cname = "EVP_PKEY", lower_case_cprefix = "EVP_PKEY_", cprefix = "EVP_PKEY_", ref_function = "EVP_PKEY_up_ref", ref_function_void = true, unref_function = "EVP_PKEY_free")]
+        public class Key {
+            public Key ();
+            [CCode (cheader_filename = "openssl_utils.h")]
+            public Key.generate_ecdsa (string curve);
+        }
+        [Compact]
+        [CCode (cname = "EVP_MD", lower_case_cprefix = "EVP_MD_", cprefix = "EVP_MD_", ref_function = "EVP_MD_up_ref", ref_function_void = true, unref_function = "EVP_MD_free")]
+        public class MessageDigest {
+        }
+
+        public static unowned MessageDigest sha256 ();
+    }
+
+    [Compact]
+    [CCode (cname = "SSL", lower_case_cprefix = "SSL_", cprefix = "SSL_", ref_function = "SSL_up_ref", ref_function_void = true, unref_function = "SSL_free", cheader_filename = "openssl/ssl.h")]
+    class SSL {
+        [Compact]
+        [CCode (cname = "SSL_CTX", lower_case_cprefix = "SSL_CTX_", cprefix = "SSL_CTX_", ref_function = "SSL_CTX_up_ref", ref_function_void = true, unref_function = "SSL_CTX_free")]
+        public class Context {
+            public Context (Method method);
+            public int set_tlsext_use_srtp (string profiles);
+            public int use_certificate (X509.Certificate certificate);
+            [CCode (cname = "SSL_CTX_use_PrivateKey")]
+            public int use_private_key (EVP.Key private_key);
+        }
+
+        [CCode (cname = "const SSL_METHOD*")]
+        public enum Method {
+            [CCode (cname = "DTLS_client_method()")]
+            DTLS_CLIENT,
+            [CCode (cname = "DTLS_server_method()")]
+            DTLS_SERVER,
+        }
+
+        [CCode (cname = "int", has_type_id = false)]
+        public enum Error {
+            NONE,
+            ZERO_RETURN,
+            WANT_READ,
+            WANT_WRITE,
+            WANT_CONNECT,
+            WANT_ACCEPT,
+            WANT_X509_LOOKUP,
+            WANT_ASYNC,
+            WANT_ASYNC_JOB,
+            WANT_CLIENT_HELLO_CB,
+            SYSCALL,
+            SSL
+        }
+
+        public SSL (Context context);
+        public BIO rbio { get; [CCode (cname="SSL_set0_rbio")] owned set; }
+        public BIO wbio { get; [CCode (cname="SSL_set0_wbio")] owned set; }
+
+        [CCode (cname = "SSL_do_handshake")]
+        private int do_handshake_ ();
+        [CCode (cname = "SSL_do_handshake_")]
+        public Error do_handshake () throws GLib.Error {
+            int ret = throw_if_error (do_handshake_ ());
+            return get_error (ret);
+        }
+        [CCode (cname = "SSL_export_keying_material")]
+        private int export_keying_material_ (uint8[] out, string label, size_t llen, [CCode (type = "const unsigned char *")] string context, size_t contextlen, bool use_context);
+        [CCode (cname = "SSL_export_keying_material_")]
+        public void export_keying_material (uint8[] out, string label, string? context = null) throws GLib.Error {
+            throw_if_error (export_keying_material_ (@out, label, label.length, context, context == null ? 0 : context.length, context != null));
+        }
+        public Error get_error (int ret);
+        public void set_accept_state ();
+        public void set_connect_state ();
+        public int want ();
+    }
+
+    [CCode (cprefix = "X509_", lower_case_cprefix = "X509_", cheader_filename = "openssl/x509.h")]
+    namespace X509 {
+        [Compact]
+        [CCode (cname = "X509", lower_case_cprefix = "X509_", cprefix = "X509_", ref_function = "X509_up_ref", ref_function_void = true, unref_function = "X509_free")]
+        public class Certificate {
+            public Certificate ();
+            public ASN1.Time not_before {
+                [CCode (cname = "X509_get_notBefore")]
+                get;
+                [CCode (cname = "X509_set_notBefore")]
+                set;
+            }
+            public ASN1.Time not_after {
+                [CCode (cname = "X509_get_notAfter")]
+                get;
+                [CCode (cname = "X509_set_notAfter")]
+                set;
+            }
+            public ASN1.Integer serial_number {
+                [CCode (cname = "X509_get_serialNumber")]
+                get;
+                [CCode (cname = "X509_set_serialNumber")]
+                set;
+            }
+            [CCode (cname = "X509_digest")]
+            private int digest_ (EVP.MessageDigest type, uchar* md, ref uint len);
+            [CCode (cname = "X509_digest_")]
+            public uint8[] digest (EVP.MessageDigest type, size_t buf_len = 512) throws GLib.Error {
+                uint8[] buf = new uint8[buf_len];
+                uint buf_out_size = (uint) buf_len;
+                throw_if_error (digest_ (type, (uchar*) buf, ref buf_out_size));
+
+                uint8[] ret = new uint8[buf_out_size];
+                for (int i = 0; i < buf_out_size; i++) {
+                    ret[i] = buf[i];
+                }
+                return ret;
+            }
+            [CCode (cname = "X509_set_pubkey")]
+            public int set_public_key (EVP.Key public_key);
+            public int set_version (long version);
+            [CCode (cname = "X509_sign")]
+            private int sign_ (EVP.Key private_key, EVP.MessageDigest md);
+            [CCode (cname = "X509_sign_")]
+            public void sign (EVP.Key private_key, EVP.MessageDigest md) throws GLib.Error {
+                throw_if_error (sign_ (private_key, md));
+            }
+        }
+    }
+
+    public int throw_if_error(int res) throws GLib.Error {
+        if (res <= 0) {
+            ulong error = ERR.get_error ();
+            if (error == 0) return res;
+            throw new GLib.Error (-1, (int) error, "%s:%s", ERR.lib_error_string (error), ERR.reason_error_string (error));
+        }
+        return res;
+    }
+}
\ No newline at end of file
diff --git a/plugins/omemo/meson.build b/plugins/omemo/meson.build
index 8a00fb1a..d195525e 100644
--- a/plugins/omemo/meson.build
+++ b/plugins/omemo/meson.build
@@ -7,7 +7,6 @@ dependencies = [
     dep_glib,
     dep_gmodule,
     dep_gtk4,
-    dep_libgcrypt,
     dep_libqrencode,
     dep_libomemo_c,
     dep_m,
@@ -62,6 +61,13 @@ c_args = vala_c_args + [
     '-DGETTEXT_PACKAGE="dino-omemo"',
     '-DLOCALE_INSTALL_DIR="@0@"'.format(get_option('prefix') / get_option('localedir')),
 ]
+if crypto_backend == 'gnutls'
+    dependencies += [ dep_libgcrypt ]
+    sources += files('src/native/helper_gcrypt.c')
+else
+    dependencies += [ dep_openssl ]
+    sources += files('src/native/helper_openssl.c')
+endif
 vala_args = [
     '--vapidir', meson.current_source_dir() / 'vapi',
     # This is to build internal vapi for tests
diff --git a/plugins/omemo/src/file_transfer/file_decryptor.vala b/plugins/omemo/src/file_transfer/file_decryptor.vala
index 80303789..ff96b4a3 100644
--- a/plugins/omemo/src/file_transfer/file_decryptor.vala
+++ b/plugins/omemo/src/file_transfer/file_decryptor.vala
@@ -59,7 +59,7 @@ public class OmemoFileDecryptor : FileDecryptor, Object {
             file_transfer.encryption = Encryption.OMEMO;
             debug("Decrypting file %s from %s", file_transfer.file_name, file_transfer.server_file_name);
 
-            SymmetricCipher cipher = new SymmetricCipher("AES-GCM");
+            SymmetricCipherDecryption cipher = create_symmetric_cipher_decryption("AES-GCM");
             cipher.set_key(key);
             cipher.set_iv(iv);
             return new ConverterInputStream(encrypted_stream, new SymmetricCipherDecrypter((owned) cipher, 16));
diff --git a/plugins/omemo/src/file_transfer/file_encryptor.vala b/plugins/omemo/src/file_transfer/file_encryptor.vala
index 58be7ef1..1aed752f 100644
--- a/plugins/omemo/src/file_transfer/file_encryptor.vala
+++ b/plugins/omemo/src/file_transfer/file_encryptor.vala
@@ -27,11 +27,11 @@ public class OmemoFileEncryptor : Dino.FileEncryptor, Object {
         try {
             //Create a key and use it to encrypt the file
             uint8[] iv = new uint8[IV_SIZE];
-            Plugin.get_context().randomize(iv);
+            Crypto.randomize(iv);
             uint8[] key = new uint8[KEY_SIZE];
-            Plugin.get_context().randomize(key);
+            Crypto.randomize(key);
 
-            SymmetricCipher cipher = new SymmetricCipher("AES-GCM");
+            SymmetricCipherEncryption cipher = create_symmetric_cipher_encryption("AES-GCM");
             cipher.set_key(key);
             cipher.set_iv(iv);
 
diff --git a/plugins/omemo/src/jingle/jet_omemo.vala b/plugins/omemo/src/jingle/jet_omemo.vala
index 2c364625..b1a27e15 100644
--- a/plugins/omemo/src/jingle/jet_omemo.vala
+++ b/plugins/omemo/src/jingle/jet_omemo.vala
@@ -93,19 +93,19 @@ public class AesGcmCipher : Jet.Cipher, Object {
     }
     public Jet.TransportSecret generate_random_secret() {
         uint8[] iv = new uint8[default_iv_size];
-        Omemo.Plugin.get_context().randomize(iv);
+        Crypto.randomize(iv);
         uint8[] key = new uint8[key_size];
-        Omemo.Plugin.get_context().randomize(key);
+        Crypto.randomize(key);
         return new Jet.TransportSecret(key, iv);
     }
     public InputStream wrap_input_stream(InputStream input, Jet.TransportSecret secret) requires (secret.transport_key.length == key_size) {
-        SymmetricCipher cipher = new SymmetricCipher("AES-GCM");
+        SymmetricCipherDecryption cipher = create_symmetric_cipher_decryption("AES-GCM");
         cipher.set_key(secret.transport_key);
         cipher.set_iv(secret.initialization_vector);
         return new ConverterInputStream(input, new SymmetricCipherDecrypter((owned) cipher, 16));
     }
     public OutputStream wrap_output_stream(OutputStream output, Jet.TransportSecret secret) requires (secret.transport_key.length == key_size) {
-        Crypto.SymmetricCipher cipher = new SymmetricCipher("AES-GCM");
+        SymmetricCipherEncryption cipher = create_symmetric_cipher_encryption("AES-GCM");
         cipher.set_key(secret.transport_key);
         cipher.set_iv(secret.initialization_vector);
         return new ConverterOutputStream(output, new SymmetricCipherEncrypter((owned) cipher, 16));
diff --git a/plugins/omemo/src/logic/encrypt.vala b/plugins/omemo/src/logic/encrypt.vala
index e5d11c69..94203ac9 100644
--- a/plugins/omemo/src/logic/encrypt.vala
+++ b/plugins/omemo/src/logic/encrypt.vala
@@ -26,9 +26,9 @@ namespace Dino.Plugins.Omemo {
 
             //Create a key and use it to encrypt the message
             uint8[] key = new uint8[KEY_SIZE];
-            Plugin.get_context().randomize(key);
+            Crypto.randomize(key);
             uint8[] iv = new uint8[IV_SIZE];
-            Plugin.get_context().randomize(iv);
+            Crypto.randomize(iv);
 
             uint8[] aes_encrypt_result = aes_encrypt(Cipher.AES_GCM_NOPADDING, key, iv, plaintext.data);
             uint8[] ciphertext = aes_encrypt_result[0:aes_encrypt_result.length - 16];
@@ -128,4 +128,4 @@ namespace Dino.Plugins.Omemo {
             encryption_data.add_device_key(device_id, device_key.serialized, device_key.type == CiphertextType.PREKEY);
         }
     }
-}
\ No newline at end of file
+}
diff --git a/plugins/omemo/src/native/context.vala b/plugins/omemo/src/native/context.vala
index b1f5945b..29a96bc1 100644
--- a/plugins/omemo/src/native/context.vala
+++ b/plugins/omemo/src/native/context.vala
@@ -1,7 +1,7 @@
 namespace Omemo {
 
 public class Context {
-    internal NativeContext native_context;
+    public NativeContext native_context;
     private RecMutex mutex = RecMutex();
 
     static void locking_function_lock(void* user_data) {
@@ -29,10 +29,6 @@ public class Context {
         return new Store(this);
     }
 
-    public void randomize(uint8[] data) throws Error {
-        throw_by_code(native_random(data));
-    }
-
     public SignedPreKeyRecord generate_signed_pre_key(IdentityKeyPair identity_key_pair, int32 id, uint64 timestamp = 0) throws Error {
         if (timestamp == 0) timestamp = new DateTime.now_utc().to_unix();
         SignedPreKeyRecord res;
diff --git a/plugins/omemo/src/native/helper.c b/plugins/omemo/src/native/helper.c
index 2d808cde..020e39d0 100644
--- a/plugins/omemo/src/native/helper.c
+++ b/plugins/omemo/src/native/helper.c
@@ -1,7 +1,5 @@
 #include "helper.h"
 
-#include <gcrypt.h>
-
 signal_type_base* signal_type_ref_vapi(void* instance) {
     g_return_val_if_fail(instance != NULL, NULL);
     signal_type_ref(instance);
@@ -64,266 +62,3 @@ void signal_protocol_address_set_device_id(signal_protocol_address* self, int32_
     self->device_id = device_id;
 }
 
-int signal_vala_randomize(uint8_t *data, size_t len) {
-    gcry_randomize(data, len, GCRY_STRONG_RANDOM);
-    return SG_SUCCESS;
-}
-
-int signal_vala_random_generator(uint8_t *data, size_t len, void *user_data) {
-    gcry_randomize(data, len, GCRY_STRONG_RANDOM);
-    return SG_SUCCESS;
-}
-
-int signal_vala_hmac_sha256_init(void **hmac_context, const uint8_t *key, size_t key_len, void *user_data) {
-    gcry_mac_hd_t* ctx = malloc(sizeof(gcry_mac_hd_t));
-    if (!ctx) return SG_ERR_NOMEM;
-
-    if (gcry_mac_open(ctx, GCRY_MAC_HMAC_SHA256, 0, 0)) {
-        free(ctx);
-        return SG_ERR_UNKNOWN;
-    }
-
-    if (gcry_mac_setkey(*ctx, key, key_len)) {
-        free(ctx);
-        return SG_ERR_UNKNOWN;
-    }
-
-    *hmac_context = ctx;
-
-    return SG_SUCCESS;
-}
-
-int signal_vala_hmac_sha256_update(void *hmac_context, const uint8_t *data, size_t data_len, void *user_data) {
-    gcry_mac_hd_t* ctx = hmac_context;
-
-    if (gcry_mac_write(*ctx, data, data_len)) return SG_ERR_UNKNOWN;
-
-    return SG_SUCCESS;
-}
-
-int signal_vala_hmac_sha256_final(void *hmac_context, signal_buffer **output, void *user_data) {
-    size_t len = gcry_mac_get_algo_maclen(GCRY_MAC_HMAC_SHA256);
-    uint8_t md[len];
-    gcry_mac_hd_t* ctx = hmac_context;
-
-    if (gcry_mac_read(*ctx, md, &len)) return SG_ERR_UNKNOWN;
-
-    signal_buffer *output_buffer = signal_buffer_create(md, len);
-    if (!output_buffer) return SG_ERR_NOMEM;
-
-    *output = output_buffer;
-
-    return SG_SUCCESS;
-}
-
-void signal_vala_hmac_sha256_cleanup(void *hmac_context, void *user_data) {
-    gcry_mac_hd_t* ctx = hmac_context;
-    if (ctx) {
-        gcry_mac_close(*ctx);
-        free(ctx);
-    }
-}
-
-const int aes_cipher(int cipher, size_t key_len, int* algo, int* mode) {
-    switch (key_len) {
-        case 16:
-            *algo = GCRY_CIPHER_AES128;
-            break;
-        case 24:
-            *algo = GCRY_CIPHER_AES192;
-            break;
-        case 32:
-            *algo = GCRY_CIPHER_AES256;
-            break;
-        default:
-            return SG_ERR_UNKNOWN;
-    }
-    switch (cipher) {
-        case SG_CIPHER_AES_CBC_PKCS5:
-            *mode = GCRY_CIPHER_MODE_CBC;
-            break;
-        case SG_CIPHER_AES_CTR_NOPADDING:
-            *mode = GCRY_CIPHER_MODE_CTR;
-            break;
-        case SG_CIPHER_AES_GCM_NOPADDING:
-            *mode = GCRY_CIPHER_MODE_GCM;
-            break;
-        default:
-            return SG_ERR_UNKNOWN;
-    }
-    return SG_SUCCESS;
-}
-
-int signal_vala_encrypt(signal_buffer **output,
-        int cipher,
-        const uint8_t *key, size_t key_len,
-        const uint8_t *iv, size_t iv_len,
-        const uint8_t *plaintext, size_t plaintext_len,
-        void *user_data) {
-    int algo, mode, error_code = SG_ERR_UNKNOWN;
-    if (aes_cipher(cipher, key_len, &algo, &mode)) return SG_ERR_INVAL;
-
-    gcry_cipher_hd_t ctx = {0};
-
-    if (gcry_cipher_open(&ctx, algo, mode, 0)) return SG_ERR_NOMEM;
-
-    signal_buffer* padded = 0;
-    signal_buffer* out_buf = 0;
-    goto no_error;
-error:
-    gcry_cipher_close(ctx);
-    if (padded != 0) {
-        signal_buffer_bzero_free(padded);
-    }
-    if (out_buf != 0) {
-        signal_buffer_free(out_buf);
-    }
-    return error_code;
-no_error:
-
-    if (gcry_cipher_setkey(ctx, key, key_len)) goto error;
-
-    uint8_t tag_len = 0, pad_len = 0;
-    switch (cipher) {
-        case SG_CIPHER_AES_CBC_PKCS5:
-            if (gcry_cipher_setiv(ctx, iv, iv_len)) goto error;
-            pad_len = 16 - (plaintext_len % 16);
-            if (pad_len == 0) pad_len = 16;
-            break;
-        case SG_CIPHER_AES_CTR_NOPADDING:
-            if (gcry_cipher_setctr(ctx, iv, iv_len)) goto error;
-            break;
-        case SG_CIPHER_AES_GCM_NOPADDING:
-            if (gcry_cipher_setiv(ctx, iv, iv_len)) goto error;
-            tag_len = 16;
-            break;
-        default:
-            return SG_ERR_UNKNOWN;
-    }
-
-    size_t padded_len = plaintext_len + pad_len;
-    padded = signal_buffer_alloc(padded_len);
-    if (padded == 0) {
-        error_code = SG_ERR_NOMEM;
-        goto error;
-    }
-
-    memset(signal_buffer_data(padded) + plaintext_len, pad_len, pad_len);
-    memcpy(signal_buffer_data(padded), plaintext, plaintext_len);
-
-    out_buf = signal_buffer_alloc(padded_len + tag_len);
-    if (out_buf == 0) {
-        error_code = SG_ERR_NOMEM;
-        goto error;
-    }
-
-    if (gcry_cipher_encrypt(ctx, signal_buffer_data(out_buf), padded_len, signal_buffer_data(padded), padded_len)) goto error;
-
-    if (tag_len > 0) {
-        if (gcry_cipher_gettag(ctx, signal_buffer_data(out_buf) + padded_len, tag_len)) goto error;
-    }
-
-    *output = out_buf;
-    out_buf = 0;
-
-    signal_buffer_bzero_free(padded);
-    padded = 0;
-
-    gcry_cipher_close(ctx);
-    return SG_SUCCESS;
-}
-
-int signal_vala_decrypt(signal_buffer **output,
-        int cipher,
-        const uint8_t *key, size_t key_len,
-        const uint8_t *iv, size_t iv_len,
-        const uint8_t *ciphertext, size_t ciphertext_len,
-        void *user_data) {
-    int algo, mode, error_code = SG_ERR_UNKNOWN;
-    *output = 0;
-    if (aes_cipher(cipher, key_len, &algo, &mode)) return SG_ERR_INVAL;
-    if (ciphertext_len == 0) return SG_ERR_INVAL;
-
-    gcry_cipher_hd_t ctx = {0};
-
-    if (gcry_cipher_open(&ctx, algo, mode, 0)) return SG_ERR_NOMEM;
-
-    signal_buffer* out_buf = 0;
-    goto no_error;
-error:
-    gcry_cipher_close(ctx);
-    if (out_buf != 0) {
-        signal_buffer_bzero_free(out_buf);
-    }
-    return error_code;
-no_error:
-
-    if (gcry_cipher_setkey(ctx, key, key_len)) goto error;
-
-    uint8_t tag_len = 0, pkcs_pad = FALSE;
-    switch (cipher) {
-        case SG_CIPHER_AES_CBC_PKCS5:
-            if (gcry_cipher_setiv(ctx, iv, iv_len)) goto error;
-            pkcs_pad = TRUE;
-            break;
-        case SG_CIPHER_AES_CTR_NOPADDING:
-            if (gcry_cipher_setctr(ctx, iv, iv_len)) goto error;
-            break;
-        case SG_CIPHER_AES_GCM_NOPADDING:
-            if (gcry_cipher_setiv(ctx, iv, iv_len)) goto error;
-            if (ciphertext_len < 16) goto error;
-            tag_len = 16;
-            break;
-        default:
-            goto error;
-    }
-
-    size_t padded_len = ciphertext_len - tag_len;
-    out_buf = signal_buffer_alloc(padded_len);
-    if (out_buf == 0) {
-        error_code = SG_ERR_NOMEM;
-        goto error;
-    }
-
-    if (gcry_cipher_decrypt(ctx, signal_buffer_data(out_buf), signal_buffer_len(out_buf), ciphertext, padded_len)) goto error;
-
-    if (tag_len > 0) {
-        if (gcry_cipher_checktag(ctx, ciphertext + padded_len, tag_len)) goto error;
-    }
-
-    if (pkcs_pad) {
-        uint8_t pad_len = signal_buffer_data(out_buf)[padded_len - 1];
-        if (pad_len > 16 || pad_len > padded_len) goto error;
-        *output = signal_buffer_create(signal_buffer_data(out_buf), padded_len - pad_len);
-        signal_buffer_bzero_free(out_buf);
-        out_buf = 0;
-    } else {
-        *output = out_buf;
-        out_buf = 0;
-    }
-
-    gcry_cipher_close(ctx);
-    return SG_SUCCESS;
-}
-
-void setup_signal_vala_crypto_provider(signal_context *context)
-{
-    gcry_check_version(NULL);
-
-    signal_crypto_provider provider = {
-            .random_func = signal_vala_random_generator,
-            .hmac_sha256_init_func = signal_vala_hmac_sha256_init,
-            .hmac_sha256_update_func = signal_vala_hmac_sha256_update,
-            .hmac_sha256_final_func = signal_vala_hmac_sha256_final,
-            .hmac_sha256_cleanup_func = signal_vala_hmac_sha256_cleanup,
-            .sha512_digest_init_func = NULL,
-            .sha512_digest_update_func = NULL,
-            .sha512_digest_final_func = NULL,
-            .sha512_digest_cleanup_func = NULL,
-            .encrypt_func = signal_vala_encrypt,
-            .decrypt_func = signal_vala_decrypt,
-            .user_data = 0
-    };
-
-    signal_context_set_crypto_provider(context, &provider);
-}
diff --git a/plugins/omemo/src/native/helper.h b/plugins/omemo/src/native/helper.h
index 3cc21d8a..cbbe220f 100644
--- a/plugins/omemo/src/native/helper.h
+++ b/plugins/omemo/src/native/helper.h
@@ -17,7 +17,6 @@ gchar* signal_protocol_address_get_name(signal_protocol_address* self);
 void signal_protocol_address_set_device_id(signal_protocol_address* self, int32_t device_id);
 int32_t signal_protocol_address_get_device_id(signal_protocol_address* self);
 
-int signal_vala_randomize(uint8_t *data, size_t len);
 int signal_vala_random_generator(uint8_t *data, size_t len, void *user_data);
 int signal_vala_hmac_sha256_init(void **hmac_context, const uint8_t *key, size_t key_len, void *user_data);
 int signal_vala_hmac_sha256_update(void *hmac_context, const uint8_t *data, size_t data_len, void *user_data);
diff --git a/plugins/omemo/src/native/helper_gcrypt.c b/plugins/omemo/src/native/helper_gcrypt.c
new file mode 100644
index 00000000..a6921bca
--- /dev/null
+++ b/plugins/omemo/src/native/helper_gcrypt.c
@@ -0,0 +1,257 @@
+#include "helper.h"
+#include <gcrypt.h>
+
+int signal_vala_random_generator(uint8_t *data, size_t len, void *user_data) {
+    gcry_randomize(data, len, GCRY_STRONG_RANDOM);
+    return SG_SUCCESS;
+}
+
+int signal_vala_hmac_sha256_init(void **hmac_context, const uint8_t *key, size_t key_len, void *user_data) {
+    gcry_mac_hd_t* ctx = malloc(sizeof(gcry_mac_hd_t));
+    if (!ctx) return SG_ERR_NOMEM;
+
+    if (gcry_mac_open(ctx, GCRY_MAC_HMAC_SHA256, 0, 0)) {
+        free(ctx);
+        return SG_ERR_UNKNOWN;
+    }
+
+    if (gcry_mac_setkey(*ctx, key, key_len)) {
+        free(ctx);
+        return SG_ERR_UNKNOWN;
+    }
+
+    *hmac_context = ctx;
+
+    return SG_SUCCESS;
+}
+
+int signal_vala_hmac_sha256_update(void *hmac_context, const uint8_t *data, size_t data_len, void *user_data) {
+    gcry_mac_hd_t* ctx = hmac_context;
+
+    if (gcry_mac_write(*ctx, data, data_len)) return SG_ERR_UNKNOWN;
+
+    return SG_SUCCESS;
+}
+
+int signal_vala_hmac_sha256_final(void *hmac_context, signal_buffer **output, void *user_data) {
+    size_t len = gcry_mac_get_algo_maclen(GCRY_MAC_HMAC_SHA256);
+    uint8_t md[len];
+    gcry_mac_hd_t* ctx = hmac_context;
+
+    if (gcry_mac_read(*ctx, md, &len)) return SG_ERR_UNKNOWN;
+
+    signal_buffer *output_buffer = signal_buffer_create(md, len);
+    if (!output_buffer) return SG_ERR_NOMEM;
+
+    *output = output_buffer;
+
+    return SG_SUCCESS;
+}
+
+void signal_vala_hmac_sha256_cleanup(void *hmac_context, void *user_data) {
+    gcry_mac_hd_t* ctx = hmac_context;
+    if (ctx) {
+        gcry_mac_close(*ctx);
+        free(ctx);
+    }
+}
+
+static int aes_cipher(int cipher, size_t key_len, int* algo, int* mode) {
+    switch (key_len) {
+        case 16:
+            *algo = GCRY_CIPHER_AES128;
+            break;
+        case 24:
+            *algo = GCRY_CIPHER_AES192;
+            break;
+        case 32:
+            *algo = GCRY_CIPHER_AES256;
+            break;
+        default:
+            return SG_ERR_UNKNOWN;
+    }
+    switch (cipher) {
+        case SG_CIPHER_AES_CBC_PKCS5:
+            *mode = GCRY_CIPHER_MODE_CBC;
+            break;
+        case SG_CIPHER_AES_CTR_NOPADDING:
+            *mode = GCRY_CIPHER_MODE_CTR;
+            break;
+        case SG_CIPHER_AES_GCM_NOPADDING:
+            *mode = GCRY_CIPHER_MODE_GCM;
+            break;
+        default:
+            return SG_ERR_UNKNOWN;
+    }
+    return SG_SUCCESS;
+}
+
+int signal_vala_encrypt(signal_buffer **output,
+        int cipher,
+        const uint8_t *key, size_t key_len,
+        const uint8_t *iv, size_t iv_len,
+        const uint8_t *plaintext, size_t plaintext_len,
+        void *user_data) {
+    int algo, mode, error_code = SG_ERR_UNKNOWN;
+    if (aes_cipher(cipher, key_len, &algo, &mode)) return SG_ERR_INVAL;
+
+    gcry_cipher_hd_t ctx = {0};
+
+    if (gcry_cipher_open(&ctx, algo, mode, 0)) return SG_ERR_NOMEM;
+
+    signal_buffer* padded = 0;
+    signal_buffer* out_buf = 0;
+    goto no_error;
+error:
+    gcry_cipher_close(ctx);
+    if (padded != 0) {
+        signal_buffer_bzero_free(padded);
+    }
+    if (out_buf != 0) {
+        signal_buffer_free(out_buf);
+    }
+    return error_code;
+no_error:
+
+    if (gcry_cipher_setkey(ctx, key, key_len)) goto error;
+
+    uint8_t tag_len = 0, pad_len = 0;
+    switch (cipher) {
+        case SG_CIPHER_AES_CBC_PKCS5:
+            if (gcry_cipher_setiv(ctx, iv, iv_len)) goto error;
+            pad_len = 16 - (plaintext_len % 16);
+            if (pad_len == 0) pad_len = 16;
+            break;
+        case SG_CIPHER_AES_CTR_NOPADDING:
+            if (gcry_cipher_setctr(ctx, iv, iv_len)) goto error;
+            break;
+        case SG_CIPHER_AES_GCM_NOPADDING:
+            if (gcry_cipher_setiv(ctx, iv, iv_len)) goto error;
+            tag_len = 16;
+            break;
+        default:
+            return SG_ERR_UNKNOWN;
+    }
+
+    size_t padded_len = plaintext_len + pad_len;
+    padded = signal_buffer_alloc(padded_len);
+    if (padded == 0) {
+        error_code = SG_ERR_NOMEM;
+        goto error;
+    }
+
+    memset(signal_buffer_data(padded) + plaintext_len, pad_len, pad_len);
+    memcpy(signal_buffer_data(padded), plaintext, plaintext_len);
+
+    out_buf = signal_buffer_alloc(padded_len + tag_len);
+    if (out_buf == 0) {
+        error_code = SG_ERR_NOMEM;
+        goto error;
+    }
+
+    if (gcry_cipher_encrypt(ctx, signal_buffer_data(out_buf), padded_len, signal_buffer_data(padded), padded_len)) goto error;
+
+    if (tag_len > 0) {
+        if (gcry_cipher_gettag(ctx, signal_buffer_data(out_buf) + padded_len, tag_len)) goto error;
+    }
+
+    *output = out_buf;
+    out_buf = 0;
+
+    signal_buffer_bzero_free(padded);
+    padded = 0;
+
+    gcry_cipher_close(ctx);
+    return SG_SUCCESS;
+}
+
+int signal_vala_decrypt(signal_buffer **output,
+        int cipher,
+        const uint8_t *key, size_t key_len,
+        const uint8_t *iv, size_t iv_len,
+        const uint8_t *ciphertext, size_t ciphertext_len,
+        void *user_data) {
+    int algo, mode, error_code = SG_ERR_UNKNOWN;
+    *output = 0;
+    if (aes_cipher(cipher, key_len, &algo, &mode)) return SG_ERR_INVAL;
+    if (ciphertext_len == 0) return SG_ERR_INVAL;
+
+    gcry_cipher_hd_t ctx = {0};
+
+    if (gcry_cipher_open(&ctx, algo, mode, 0)) return SG_ERR_NOMEM;
+
+    signal_buffer* out_buf = 0;
+    goto no_error;
+error:
+    gcry_cipher_close(ctx);
+    if (out_buf != 0) {
+        signal_buffer_bzero_free(out_buf);
+    }
+    return error_code;
+no_error:
+
+    if (gcry_cipher_setkey(ctx, key, key_len)) goto error;
+
+    uint8_t tag_len = 0, pkcs_pad = FALSE;
+    switch (cipher) {
+        case SG_CIPHER_AES_CBC_PKCS5:
+            if (gcry_cipher_setiv(ctx, iv, iv_len)) goto error;
+            pkcs_pad = TRUE;
+            break;
+        case SG_CIPHER_AES_CTR_NOPADDING:
+            if (gcry_cipher_setctr(ctx, iv, iv_len)) goto error;
+            break;
+        case SG_CIPHER_AES_GCM_NOPADDING:
+            if (gcry_cipher_setiv(ctx, iv, iv_len)) goto error;
+            if (ciphertext_len < 16) goto error;
+            tag_len = 16;
+            break;
+        default:
+            goto error;
+    }
+
+    size_t padded_len = ciphertext_len - tag_len;
+    out_buf = signal_buffer_alloc(padded_len);
+    if (out_buf == 0) {
+        error_code = SG_ERR_NOMEM;
+        goto error;
+    }
+
+    if (gcry_cipher_decrypt(ctx, signal_buffer_data(out_buf), signal_buffer_len(out_buf), ciphertext, padded_len)) goto error;
+
+    if (tag_len > 0) {
+        if (gcry_cipher_checktag(ctx, ciphertext + padded_len, tag_len)) goto error;
+    }
+
+    if (pkcs_pad) {
+        uint8_t pad_len = signal_buffer_data(out_buf)[padded_len - 1];
+        if (pad_len > 16 || pad_len > padded_len) goto error;
+        *output = signal_buffer_create(signal_buffer_data(out_buf), padded_len - pad_len);
+        signal_buffer_bzero_free(out_buf);
+        out_buf = 0;
+    } else {
+        *output = out_buf;
+        out_buf = 0;
+    }
+
+    gcry_cipher_close(ctx);
+    return SG_SUCCESS;
+}
+
+void setup_signal_vala_crypto_provider(signal_context *context) {
+    gcry_check_version(NULL);
+
+    signal_crypto_provider provider = {
+            .random_func = signal_vala_random_generator,
+            .hmac_sha256_init_func = signal_vala_hmac_sha256_init,
+            .hmac_sha256_update_func = signal_vala_hmac_sha256_update,
+            .hmac_sha256_final_func = signal_vala_hmac_sha256_final,
+            .hmac_sha256_cleanup_func = signal_vala_hmac_sha256_cleanup,
+            .encrypt_func = signal_vala_encrypt,
+            .decrypt_func = signal_vala_decrypt,
+            .user_data = 0
+    };
+
+    signal_context_set_crypto_provider(context, &provider);
+}
+
diff --git a/plugins/omemo/src/native/helper_openssl.c b/plugins/omemo/src/native/helper_openssl.c
new file mode 100644
index 00000000..a0020971
--- /dev/null
+++ b/plugins/omemo/src/native/helper_openssl.c
@@ -0,0 +1,313 @@
+#include "helper.h"
+#include <openssl/evp.h>
+#include <openssl/rand.h>
+
+int signal_vala_random_generator(uint8_t *data, size_t len, void *user_data) {
+    return RAND_bytes(data, len) == 1 ? SG_SUCCESS : SG_ERR_UNKNOWN;
+}
+
+struct SIGNAL_VALA_HMAC_CTX {
+    EVP_PKEY *pkey;
+    EVP_MD_CTX *ctx;
+};
+
+int signal_vala_hmac_sha256_init(void **hmac_context, const uint8_t *key, size_t key_len, void *user_data) {
+    EVP_PKEY *pkey = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL, key, key_len);
+    if (!pkey) {
+        return SG_ERR_NOMEM;
+    }
+    EVP_MD_CTX *ctx = EVP_MD_CTX_new();
+    if (!ctx) {
+        EVP_PKEY_free(pkey);
+        return SG_ERR_NOMEM;
+    }
+    if (EVP_DigestSignInit(ctx, NULL, EVP_sha256(), NULL, pkey) != 1) {
+        EVP_MD_CTX_free(ctx);
+        EVP_PKEY_free(pkey);
+        return SG_ERR_UNKNOWN;
+    }
+
+    struct SIGNAL_VALA_HMAC_CTX *hmac_ctx = malloc(sizeof(*hmac_ctx));
+    hmac_ctx->pkey = pkey;
+    hmac_ctx->ctx = ctx;
+    *hmac_context = hmac_ctx;
+
+    return SG_SUCCESS;
+}
+
+int signal_vala_hmac_sha256_update(void *hmac_context, const uint8_t *data, size_t data_len, void *user_data) {
+    struct SIGNAL_VALA_HMAC_CTX *hmac_ctx = hmac_context;
+    if (EVP_DigestSignUpdate(hmac_ctx->ctx, data, data_len) != 1) {
+        return SG_ERR_UNKNOWN;
+    }
+    return SG_SUCCESS;
+}
+
+int signal_vala_hmac_sha256_final(void *hmac_context, signal_buffer **output, void *user_data) {
+    size_t len;
+    struct SIGNAL_VALA_HMAC_CTX *hmac_ctx = hmac_context;
+    if (EVP_DigestSignFinal(hmac_ctx->ctx, NULL, &len) != 1) {
+        return SG_ERR_UNKNOWN;
+    }
+    signal_buffer *output_buffer = signal_buffer_alloc(len);
+    if (!output_buffer) {
+        return SG_ERR_NOMEM;
+    }
+    size_t another_len = len;
+    if (EVP_DigestSignFinal(hmac_ctx->ctx, signal_buffer_data(output_buffer), &another_len) != 1) {
+        signal_buffer_free(output_buffer);
+        return SG_ERR_UNKNOWN;
+    }
+    if (another_len != len) {
+        signal_buffer_free(output_buffer);
+        return SG_ERR_UNKNOWN;
+    }
+    *output = output_buffer;
+    return SG_SUCCESS;
+}
+
+void signal_vala_hmac_sha256_cleanup(void *hmac_context, void *user_data) {
+    struct SIGNAL_VALA_HMAC_CTX *hmac_ctx = hmac_context;
+    if (hmac_ctx) {
+        EVP_MD_CTX_free(hmac_ctx->ctx);
+        EVP_PKEY_free(hmac_ctx->pkey);
+        free(hmac_ctx);
+    }
+}
+
+static const EVP_CIPHER *aes_cipher(int cipher, size_t key_len) {
+    switch (cipher) {
+        case SG_CIPHER_AES_CBC_PKCS5:
+            switch (key_len) {
+                case 16: return EVP_aes_128_cbc();
+                case 24: return EVP_aes_192_cbc();
+                case 32: return EVP_aes_256_cbc();
+            }
+            break;
+        case SG_CIPHER_AES_CTR_NOPADDING:
+            switch (key_len) {
+                case 16: return EVP_aes_128_ctr();
+                case 24: return EVP_aes_192_ctr();
+                case 32: return EVP_aes_256_ctr();
+            }
+            break;
+        case SG_CIPHER_AES_GCM_NOPADDING:
+            switch (key_len) {
+                case 16: return EVP_aes_128_gcm();
+                case 24: return EVP_aes_192_gcm();
+                case 32: return EVP_aes_256_gcm();
+            }
+            break;
+
+    }
+    return NULL;
+}
+
+int signal_vala_encrypt(signal_buffer **output,
+        int cipher,
+        const uint8_t *key, size_t key_len,
+        const uint8_t *iv, size_t iv_len,
+        const uint8_t *plaintext, size_t plaintext_len,
+        void *user_data) {
+    int result = 0;
+    uint8_t *out_buf = NULL;
+    const EVP_CIPHER *evp_cipher = aes_cipher(cipher, key_len);
+    if (!evp_cipher) {
+        // fprintf(stderr, "invalid AES mode or key size: %zu\n", key_len);
+        return SG_ERR_INVAL;
+    }
+    if (plaintext_len > INT_MAX - EVP_CIPHER_block_size(evp_cipher)) {
+        // fprintf(stderr, "invalid plaintext length: %zu\n", plaintext_len);
+        return SG_ERR_UNKNOWN;
+    }
+    EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
+    int buf_extra = 0;
+
+    if (cipher == SG_CIPHER_AES_GCM_NOPADDING) {
+        // In GCM mode we use the last 16 bytes as auth tag
+        buf_extra += 16;
+
+        if (EVP_EncryptInit_ex(ctx, evp_cipher, NULL, NULL, NULL) != 1) {
+            // fprintf(stderr, "cannot initialize cipher\n");
+            result = SG_ERR_UNKNOWN;
+            goto complete;
+        }
+
+        if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_IVLEN, iv_len, NULL) != 1) {
+            // fprintf(stderr, "cannot set iv size\n");
+            result = SG_ERR_UNKNOWN;
+            goto complete;
+        }
+
+        if (EVP_EncryptInit_ex(ctx, NULL, NULL, key, iv) != 1) {
+            // fprintf(stderr, "cannot set key/iv\n");
+            result = SG_ERR_UNKNOWN;
+            goto complete;
+        }
+    } else {
+        // TODO: set ivlen?
+        if (EVP_EncryptInit_ex(ctx, evp_cipher, 0, key, iv) != 1) {
+            // fprintf(stderr, "cannot initialize cipher\n");
+            result = SG_ERR_UNKNOWN;
+            goto complete;
+        }
+    }
+
+    if (cipher == SG_CIPHER_AES_CTR_NOPADDING || cipher == SG_CIPHER_AES_GCM_NOPADDING) {
+        if (EVP_CIPHER_CTX_set_padding(ctx, 0) != 1) {
+            // fprintf(stderr, "cannot set padding\n");
+            result = SG_ERR_UNKNOWN;
+            goto complete;
+        }
+    }
+
+    out_buf = malloc(plaintext_len + EVP_CIPHER_block_size(evp_cipher) + buf_extra);
+    if (!out_buf) {
+        // fprintf(stderr, "cannot allocate output buffer\n");
+        result = SG_ERR_NOMEM;
+        goto complete;
+    }
+
+    int out_len = 0;
+    if (EVP_EncryptUpdate(ctx, out_buf, &out_len, plaintext, plaintext_len) != 1) {
+        // fprintf(stderr, "cannot encrypt plaintext\n");
+        result = SG_ERR_UNKNOWN;
+        goto complete;
+    }
+
+    int final_len = 0;
+    if (EVP_EncryptFinal_ex(ctx, out_buf + out_len, &final_len) != 1) {
+        // fprintf(stderr, "cannot finish encrypting plaintext\n");
+        result = SG_ERR_UNKNOWN;
+        goto complete;
+    }
+
+    if (cipher == SG_CIPHER_AES_GCM_NOPADDING) {
+        if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_GET_TAG, 16, out_buf + out_len + final_len) != 1) {
+            // fprintf(stderr, "cannot get tag\n");
+            result = SG_ERR_UNKNOWN;
+            goto complete;
+        }
+    }
+
+    *output = signal_buffer_create(out_buf, out_len + final_len + buf_extra);
+
+complete:
+    EVP_CIPHER_CTX_free(ctx);
+    if (out_buf) {
+        free(out_buf);
+    }
+    return result;
+}
+
+int signal_vala_decrypt(signal_buffer **output,
+        int cipher,
+        const uint8_t *key, size_t key_len,
+        const uint8_t *iv, size_t iv_len,
+        const uint8_t *ciphertext, size_t ciphertext_len,
+        void *user_data) {
+    int result = 0;
+    uint8_t *out_buf = NULL;
+    const EVP_CIPHER *evp_cipher = aes_cipher(cipher, key_len);
+    if (!evp_cipher) {
+        // fprintf(stderr, "invalid AES mode or key size: %zu\n", key_len);
+        return SG_ERR_INVAL;
+    }
+    if (ciphertext_len > INT_MAX - EVP_CIPHER_block_size(evp_cipher)) {
+        // fprintf(stderr, "invalid ciphertext length: %zu\n", ciphertext_len);
+        return SG_ERR_UNKNOWN;
+    }
+
+    EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
+
+    if (cipher == SG_CIPHER_AES_GCM_NOPADDING) {
+        // In GCM mode we use the last 16 bytes as auth tag
+        ciphertext_len -= 16;
+
+        if (EVP_DecryptInit_ex(ctx, evp_cipher, NULL, NULL, NULL) != 1) {
+            // fprintf(stderr, "cannot initialize cipher\n");
+            result = SG_ERR_UNKNOWN;
+            goto complete;
+        }
+
+        if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_IVLEN, iv_len, NULL) != 1) {
+            // fprintf(stderr, "cannot set iv size\n");
+            result = SG_ERR_UNKNOWN;
+            goto complete;
+        }
+
+        if (EVP_DecryptInit_ex(ctx, NULL, NULL, key, iv) != 1) {
+            // fprintf(stderr, "cannot set key/iv\n");
+            result = SG_ERR_UNKNOWN;
+            goto complete;
+        }
+    } else {
+        // TODO: set ivlen?
+        if (EVP_DecryptInit_ex(ctx, evp_cipher, 0, key, iv) != 1) {
+            // fprintf(stderr, "cannot initialize cipher\n");
+            result = SG_ERR_UNKNOWN;
+            goto complete;
+        }
+    }
+
+    if (cipher == SG_CIPHER_AES_CTR_NOPADDING || cipher == SG_CIPHER_AES_GCM_NOPADDING) {
+        if (EVP_CIPHER_CTX_set_padding(ctx, 0) != 1) {
+            // fprintf(stderr, "cannot set padding\n");
+            result = SG_ERR_UNKNOWN;
+            goto complete;
+        }
+    }
+
+    out_buf = malloc(ciphertext_len + EVP_CIPHER_block_size(evp_cipher));
+    if (!out_buf) {
+        // fprintf(stderr, "cannot allocate output buffer\n");
+        result = SG_ERR_NOMEM;
+        goto complete;
+    }
+
+    int out_len = 0;
+    if (EVP_DecryptUpdate(ctx, out_buf, &out_len, ciphertext, ciphertext_len) != 1) {
+        // fprintf(stderr, "cannot decrypt ciphertext\n");
+        result = SG_ERR_UNKNOWN;
+        goto complete;
+    }
+
+    if (cipher == SG_CIPHER_AES_GCM_NOPADDING) {
+        if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_TAG, 16, (void *)(ciphertext + ciphertext_len)) != 1) {
+            // fprintf(stderr, "cannot set tag\n");
+            result = SG_ERR_UNKNOWN;
+            goto complete;
+        }
+    }
+
+    int final_len = 0;
+    if (EVP_DecryptFinal_ex(ctx, out_buf + out_len, &final_len) != 1) {
+        // fprintf(stderr, "cannot finish decrypting ciphertexts\n");
+        result = SG_ERR_UNKNOWN;
+        goto complete;
+    }
+
+    *output = signal_buffer_create(out_buf, out_len + final_len);
+
+complete:
+    EVP_CIPHER_CTX_free(ctx);
+    if (out_buf) {
+        free(out_buf);
+    }
+    return result;
+}
+
+void setup_signal_vala_crypto_provider(signal_context *context) {
+    signal_crypto_provider provider = {
+            .random_func = signal_vala_random_generator,
+            .hmac_sha256_init_func = signal_vala_hmac_sha256_init,
+            .hmac_sha256_update_func = signal_vala_hmac_sha256_update,
+            .hmac_sha256_final_func = signal_vala_hmac_sha256_final,
+            .hmac_sha256_cleanup_func = signal_vala_hmac_sha256_cleanup,
+            .encrypt_func = signal_vala_encrypt,
+            .decrypt_func = signal_vala_decrypt,
+            .user_data = 0
+    };
+
+    signal_context_set_crypto_provider(context, &provider);
+}
diff --git a/plugins/omemo/src/native/store.vala b/plugins/omemo/src/native/store.vala
index b1861d93..12f22f83 100644
--- a/plugins/omemo/src/native/store.vala
+++ b/plugins/omemo/src/native/store.vala
@@ -107,7 +107,7 @@ public class Store : Object {
     public PreKeyStore pre_key_store { get; set; default = new SimplePreKeyStore(); }
     public SignedPreKeyStore signed_pre_key_store { get; set; default = new SimpleSignedPreKeyStore(); }
     public uint32 local_registration_id { get { return identity_key_store.local_registration_id; } }
-    internal NativeStoreContext native_context {get { return native_store_context_; }}
+    public NativeStoreContext native_context {get { return native_store_context_; }}
     private NativeStoreContext native_store_context_;
 
     static int iks_get_identity_key_pair(out Buffer public_data, out Buffer private_data, void* user_data) {
diff --git a/plugins/omemo/vapi/libomemo-c.vapi b/plugins/omemo/vapi/libomemo-c.vapi
index 34bb0202..8c7a2fca 100644
--- a/plugins/omemo/vapi/libomemo-c.vapi
+++ b/plugins/omemo/vapi/libomemo-c.vapi
@@ -689,6 +689,4 @@ namespace Omemo {
 
     [CCode (cname = "setup_signal_vala_crypto_provider", cheader_filename = "native/helper.h")]
     public static void setup_crypto_provider(NativeContext context);
-    [CCode (cname = "signal_vala_randomize", cheader_filename = "native/helper.h")]
-    public static int native_random(uint8[] data);
 }
diff --git a/plugins/omemo/vapi/openssl.vapi b/plugins/omemo/vapi/openssl.vapi
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/plugins/omemo/vapi/openssl.vapi