Move crypto-vala inside libdino

8 files changed, 595 insertions, 0 deletions

diff --git a/libdino/src/crypto/cipher.vala b/libdino/src/crypto/cipher.vala
new file mode 100644
index 00000000..89282144
--- /dev/null
+++ b/libdino/src/crypto/cipher.vala
@@ -0,0 +1,19 @@
+namespace Dino.Crypto {
+
+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 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 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/libdino/src/crypto/cipher_converter.vala b/libdino/src/crypto/cipher_converter.vala
new file mode 100644
index 00000000..c2404c6d
--- /dev/null
+++ b/libdino/src/crypto/cipher_converter.vala
@@ -0,0 +1,110 @@
+using GLib;
+
+namespace Dino.Crypto {
+
+public class SymmetricCipherEncrypter : Converter, Object {
+    private SymmetricCipherEncryption cipher;
+    private size_t attached_taglen;
+
+    public SymmetricCipherEncrypter(owned SymmetricCipherEncryption cipher, size_t attached_taglen = 0) {
+        this.cipher = (owned) cipher;
+        this.attached_taglen = attached_taglen;
+    }
+
+    public void reset() {
+        try {
+            cipher.reset();
+        } catch (Crypto.Error e) {
+            warning(@"$(e.domain) error while resetting cipher: $(e.message)");
+        }
+    }
+
+    public uint8[] get_tag(size_t taglen) throws Error {
+        return ((SymmetricCipherEncryption)cipher).get_tag(taglen);
+    }
+
+    public ConverterResult convert(uint8[] inbuf, uint8[] outbuf, ConverterFlags flags, out size_t bytes_read, out size_t bytes_written) throws IOError {
+        if (inbuf.length > outbuf.length) {
+            throw new IOError.NO_SPACE("CipherConverter needs at least the size of input as output space");
+        }
+        if ((flags & ConverterFlags.INPUT_AT_END) != 0 && inbuf.length + attached_taglen > outbuf.length) {
+            throw new IOError.NO_SPACE("CipherConverter needs additional output space to attach tag");
+        }
+        try {
+            if (inbuf.length > 0) {
+                ((SymmetricCipherEncryption)cipher).encrypt(outbuf, inbuf);
+            }
+            bytes_read = inbuf.length;
+            bytes_written = inbuf.length;
+            if ((flags & ConverterFlags.INPUT_AT_END) != 0) {
+                if (attached_taglen > 0) {
+                    Memory.copy((uint8*)outbuf + inbuf.length, get_tag(attached_taglen), attached_taglen);
+                    bytes_written = inbuf.length + attached_taglen;
+                }
+                return ConverterResult.FINISHED;
+            }
+            if ((flags & ConverterFlags.FLUSH) != 0) {
+                return ConverterResult.FLUSHED;
+            }
+            return ConverterResult.CONVERTED;
+        } catch (Crypto.Error e) {
+            throw new IOError.FAILED(@"$(e.domain) error while encrypting: $(e.message)");
+        }
+    }
+}
+
+public class SymmetricCipherDecrypter : Converter, Object {
+    private SymmetricCipherDecryption cipher;
+    private size_t attached_taglen;
+
+    public SymmetricCipherDecrypter(owned SymmetricCipherDecryption cipher, size_t attached_taglen = 0) {
+        this.cipher = (owned) cipher;
+        this.attached_taglen = attached_taglen;
+    }
+
+    public void reset() {
+        try {
+            cipher.reset();
+        } catch (Crypto.Error e) {
+            warning(@"$(e.domain) error while resetting cipher: $(e.message)");
+        }
+    }
+
+    public void check_tag(uint8[] tag) throws Error {
+        ((SymmetricCipherDecryption)cipher).check_tag(tag);
+    }
+
+    public ConverterResult convert(uint8[] inbuf, uint8[] outbuf, ConverterFlags flags, out size_t bytes_read, out size_t bytes_written) throws IOError {
+        if (inbuf.length > outbuf.length + attached_taglen) {
+            throw new IOError.NO_SPACE("CipherConverter needs at least the size of input as output space");
+        }
+        if ((flags & ConverterFlags.INPUT_AT_END) != 0 && inbuf.length < attached_taglen) {
+            throw new IOError.PARTIAL_INPUT("CipherConverter needs additional input to read tag");
+        } else if ((flags & ConverterFlags.INPUT_AT_END) == 0 && inbuf.length < attached_taglen + 1) {
+            throw new IOError.PARTIAL_INPUT("CipherConverter needs additional input to make sure to not accidentally read tag");
+        }
+        try {
+            inbuf.length -= (int) attached_taglen;
+            if (inbuf.length > 0) {
+                ((SymmetricCipherDecryption)cipher).decrypt(outbuf, inbuf);
+            }
+            bytes_read = inbuf.length;
+            bytes_written = inbuf.length;
+            inbuf.length += (int) attached_taglen;
+            if ((flags & ConverterFlags.INPUT_AT_END) != 0) {
+                if (attached_taglen > 0) {
+                    check_tag(inbuf[(inbuf.length - attached_taglen):inbuf.length]);
+                    bytes_read = inbuf.length;
+                }
+                return ConverterResult.FINISHED;
+            }
+            if ((flags & ConverterFlags.FLUSH) != 0) {
+                return ConverterResult.FLUSHED;
+            }
+            return ConverterResult.CONVERTED;
+        } catch (Crypto.Error e) {
+            throw new IOError.FAILED(@"$(e.domain) error while decrypting: $(e.message)");
+        }
+    }
+}
+}
diff --git a/libdino/src/crypto/error.vala b/libdino/src/crypto/error.vala
new file mode 100644
index 00000000..2458ae4a
--- /dev/null
+++ b/libdino/src/crypto/error.vala
@@ -0,0 +1,11 @@
+namespace Dino.Crypto {
+
+public errordomain Error {
+    ILLEGAL_ARGUMENTS,
+    GCRYPT,
+    OPENSSL,
+    AUTHENTICATION_FAILED,
+    UNKNOWN
+}
+
+}
diff --git a/libdino/src/crypto/gnu/cipher.vala b/libdino/src/crypto/gnu/cipher.vala
new file mode 100644
index 00000000..41f15837
--- /dev/null
+++ b/libdino/src/crypto/gnu/cipher.vala
@@ -0,0 +1,137 @@
+namespace Dino.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/libdino/src/crypto/gnu/utils.vala b/libdino/src/crypto/gnu/utils.vala
new file mode 100644
index 00000000..8a25ab27
--- /dev/null
+++ b/libdino/src/crypto/gnu/utils.vala
@@ -0,0 +1,21 @@
+namespace Dino.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/libdino/src/crypto/openssl/cipher.vala b/libdino/src/crypto/openssl/cipher.vala
new file mode 100644
index 00000000..02064770
--- /dev/null
+++ b/libdino/src/crypto/openssl/cipher.vala
@@ -0,0 +1,156 @@
+namespace Dino.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/libdino/src/crypto/openssl/utils.vala b/libdino/src/crypto/openssl/utils.vala
new file mode 100644
index 00000000..7a9ed9b6
--- /dev/null
+++ b/libdino/src/crypto/openssl/utils.vala
@@ -0,0 +1,19 @@
+namespace Dino.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/libdino/src/crypto/srtp.vala b/libdino/src/crypto/srtp.vala
new file mode 100644
index 00000000..852dccdc
--- /dev/null
+++ b/libdino/src/crypto/srtp.vala
@@ -0,0 +1,122 @@
+using Srtp;
+
+namespace Dino.Crypto.Srtp {
+public const string AES_CM_128_HMAC_SHA1_80 = "AES_CM_128_HMAC_SHA1_80";
+public const string AES_CM_128_HMAC_SHA1_32 = "AES_CM_128_HMAC_SHA1_32";
+public const string F8_128_HMAC_SHA1_80 = "F8_128_HMAC_SHA1_80";
+
+public class Session {
+    public bool has_encrypt { get; private set; default = false; }
+    public bool has_decrypt { get; private set; default = false; }
+
+    private Context encrypt_context;
+    private Context decrypt_context;
+
+    static construct {
+        init();
+        install_log_handler(log);
+    }
+
+    private static void log(LogLevel level, string msg) {
+        print(@"SRTP[$level]: $msg\n");
+    }
+
+    public Session() {
+        Context.create(out encrypt_context, null);
+        Context.create(out decrypt_context, null);
+    }
+
+    public uint8[] encrypt_rtp(uint8[] data) throws Error {
+        uint8[] buf = new uint8[data.length + MAX_TRAILER_LEN];
+        Memory.copy(buf, data, data.length);
+        int buf_use = data.length;
+        ErrorStatus res = encrypt_context.protect(buf, ref buf_use);
+        if (res != ErrorStatus.ok) {
+            throw new Error.UNKNOWN(@"SRTP encrypt failed: $res");
+        }
+        buf.length = buf_use;
+        return buf;
+    }
+
+    public uint8[] decrypt_rtp(uint8[] data) throws Error {
+        uint8[] buf = new uint8[data.length];
+        Memory.copy(buf, data, data.length);
+        int buf_use = data.length;
+        ErrorStatus res = decrypt_context.unprotect(buf, ref buf_use);
+        switch (res) {
+            case ErrorStatus.auth_fail:
+                throw new Error.AUTHENTICATION_FAILED("SRTP packet failed the message authentication check");
+            case ErrorStatus.ok:
+                break;
+            default:
+                throw new Error.UNKNOWN(@"SRTP decrypt failed: $res");
+        }
+        uint8[] ret = new uint8[buf_use];
+        GLib.Memory.copy(ret, buf, buf_use);
+        return ret;
+    }
+
+    public uint8[] encrypt_rtcp(uint8[] data) throws Error {
+        uint8[] buf = new uint8[data.length + MAX_TRAILER_LEN + 4];
+        Memory.copy(buf, data, data.length);
+        int buf_use = data.length;
+        ErrorStatus res = encrypt_context.protect_rtcp(buf, ref buf_use);
+        if (res != ErrorStatus.ok) {
+            throw new Error.UNKNOWN(@"SRTCP encrypt failed: $res");
+        }
+        buf.length = buf_use;
+        return buf;
+    }
+
+    public uint8[] decrypt_rtcp(uint8[] data) throws Error {
+        uint8[] buf = new uint8[data.length];
+        Memory.copy(buf, data, data.length);
+        int buf_use = data.length;
+        ErrorStatus res = decrypt_context.unprotect_rtcp(buf, ref buf_use);
+        switch (res) {
+            case ErrorStatus.auth_fail:
+                throw new Error.AUTHENTICATION_FAILED("SRTCP packet failed the message authentication check");
+            case ErrorStatus.ok:
+                break;
+            default:
+                throw new Error.UNKNOWN(@"SRTCP decrypt failed: $res");
+        }
+        uint8[] ret = new uint8[buf_use];
+        GLib.Memory.copy(ret, buf, buf_use);
+        return ret;
+    }
+
+    private Policy create_policy(string profile) {
+        Policy policy = Policy();
+        switch (profile) {
+            case AES_CM_128_HMAC_SHA1_80:
+                policy.rtp.set_aes_cm_128_hmac_sha1_80();
+                policy.rtcp.set_aes_cm_128_hmac_sha1_80();
+                break;
+        }
+        return policy;
+    }
+
+    public void set_encryption_key(string profile, uint8[] key, uint8[] salt) {
+        Policy policy = create_policy(profile);
+        policy.ssrc.type = SsrcType.any_outbound;
+        policy.key = new uint8[key.length + salt.length];
+        Memory.copy(policy.key, key, key.length);
+        Memory.copy(((uint8*)policy.key) + key.length, salt, salt.length);
+        policy.next = null;
+        encrypt_context.add_stream(ref policy);
+        has_encrypt = true;
+    }
+
+    public void set_decryption_key(string profile, uint8[] key, uint8[] salt) {
+        Policy policy = create_policy(profile);
+        policy.ssrc.type = SsrcType.any_inbound;
+        policy.key = new uint8[key.length + salt.length];
+        Memory.copy(policy.key, key, key.length);
+        Memory.copy(((uint8*)policy.key) + key.length, salt, salt.length);
+        policy.next = null;
+        decrypt_context.add_stream(ref policy);
+        has_decrypt = true;
+    }
+}
+}
\ No newline at end of file