jimm98y · paulomorgado · Jan 31, 2026 · Feb 1, 2026 · Feb 1, 2026 · Feb 1, 2026
diff --git a/src/DtlsSrtpClientSample/Program.cs b/src/DtlsSrtpClientSample/Program.cs
@@ -19,45 +19,50 @@
 client.OnSessionStarted += (sender, e) =>
 {
     isSrtpSessionRunning = true;
-    socket.ReceiveTimeout = 1000; 
+    socket.ReceiveTimeout = 1000;
 
     var context = e.Context;
     var srtpSession = Task.Run(async () =>
     {
         var protectionProfile = context.DecodeRtpContext.ProtectionProfile;
         Console.WriteLine($"SRTP cipher:   {protectionProfile.Cipher}, auth: {protectionProfile.Auth}");
-        
+
         byte[] receiveBuffer = new byte[2048];
         int timeoutCounter = 0;
 
         while (!isShutdown)
         {
-            int receivedLen = 0;            
+            int receivedLen = 0;
             try
             {
                 receivedLen = socket.Receive(receiveBuffer);
                 timeoutCounter = 0;
             }
             catch (SocketException ex)
             {
-                if(ex.SocketErrorCode == SocketError.TimedOut)
+                if (ex.SocketErrorCode == SocketError.TimedOut)
                 {
                     timeoutCounter++;
                 }
             }
-                
+
             if (receivedLen != 0)
             {
                 Console.WriteLine($"SRTP: {Convert.ToHexString(receiveBuffer.Take(receivedLen).ToArray())}");
 
-                if (context.UnprotectRtp(receiveBuffer, receivedLen, out int length) == 0)
+                try
                 {
+                    var length = context.UnprotectRtp(receiveBuffer, receiveBuffer);
                     byte[] rtp = receiveBuffer.Take(length).ToArray();
                     Console.WriteLine($"RTP: {Convert.ToHexString(rtp)}");
                 }
+                catch (System.Security.Cryptography.CryptographicException ex)
+                {
+                    Console.WriteLine($"SRTP error: {ex.HResult}");
+                }
             }
 
-            if(timeoutCounter > 30)
+            if (timeoutCounter > 30)
             {
                 isSrtpSessionRunning = false;
                 break;
@@ -74,7 +79,7 @@
     {
         Console.WriteLine($"DTLS connected");
 
-        while(isSrtpSessionRunning)
+        while (isSrtpSessionRunning)
         {
             Thread.Sleep(1000);
         }

diff --git a/src/DtlsSrtpServerSample/Program.cs b/src/DtlsSrtpServerSample/Program.cs
@@ -52,12 +52,17 @@
             Buffer.BlockCopy(rtpPacket, 0, rtpBuffer, 0, rtpPacket.Length);
 
             Console.WriteLine($"RTP: {Convert.ToHexString(rtpPacket)}");
-            if (context.ProtectRtp(rtpBuffer, rtpPacket.Length, out int length) == 0)
+            try
             {
+                var length = context.ProtectRtp(rtpBuffer, rtpBuffer);
                 byte[] srtp = rtpBuffer.Take(length).ToArray();
                 Console.WriteLine($"SRTP:     {Convert.ToHexString(srtp)}");
                 listenSocket.SendTo(srtp, remoteEndpoint);
             }
+            catch (System.Security.Cryptography.CryptographicException ex)
+            {
+                Console.WriteLine($"SRTP error: {ex.HResult}");
+            }
 
             sequenceNumber++;
             Thread.Sleep(1000);

diff --git a/src/SharpSRTP.Tests/Convert.cs b/src/SharpSRTP.Tests/Convert.cs
@@ -0,0 +1,52 @@
+#if !NET5_0_OR_GREATER
+using System;
+
+namespace SharpSRTP.Tests
+{
+    internal static partial class Convert
+    {
+        internal static byte[] FromHexString(string s)
+        {
+            if (s == null) throw new ArgumentNullException(nameof(s));
+            if ((s.Length & 1) != 0) throw new FormatException("Hex string must have even length.");
+
+            int len = s.Length >> 1;
+            var bytes = new byte[len];
+            for (int i = 0, bi = 0; bi < len; i += 2, bi++)
+            {
+                int hi = ParseNibble(s[i]);
+                int lo = ParseNibble(s[i + 1]);
+                bytes[bi] = (byte)((hi << 4) | lo);
+            }
+            return bytes;
+        }
+
+        internal static string ToHexString(ReadOnlySpan<byte> bytes)
+        {
+            if (bytes == null) throw new ArgumentNullException(nameof(bytes));
+            char[] c = new char[bytes.Length * 2];
+            int ci = 0;
+            for (int i = 0; i < bytes.Length; i++)
+            {
+                byte b = bytes[i];
+                c[ci++] = NibbleToHex((b >> 4) & 0xF);
+                c[ci++] = NibbleToHex(b & 0xF);
+            }
+            return new string(c);
+        }
+
+        private static int ParseNibble(char c)
+        {
+            if (c >= '0' && c <= '9') return c - '0';
+            if (c >= 'a' && c <= 'f') return c - 'a' + 10;
+            if (c >= 'A' && c <= 'F') return c - 'A' + 10;
+            throw new FormatException("Invalid hex character.");
+        }
+
+        private static char NibbleToHex(int value)
+        {
+            return (char)(value < 10 ? ('0' + value) : ('A' + (value - 10)));
+        }
+    }
+}
+#endif
diff --git a/src/SharpSRTP.Tests/SharpSRTP.Tests.csproj b/src/SharpSRTP.Tests/SharpSRTP.Tests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net10.0</TargetFramework>
+    <TargetFrameworks>net462;net8.0</TargetFrameworks>
     <LangVersion>latest</LangVersion>
     <ImplicitUsings>disable</ImplicitUsings>
     <Nullable>disable</Nullable>

diff --git a/src/SharpSRTP.Tests/TestProtectUnprotect.cs b/src/SharpSRTP.Tests/TestProtectUnprotect.cs
@@ -22,33 +22,65 @@
 using SharpSRTP.SRTP;
 using System;
 using System.Data;
-using System.Linq;
 
 namespace SharpSRTP.Tests
 {
     [TestClass]
     public class TestProtectUnprotect
     {
-        [DataRow("n7z9GgmnJ4Bc2hC0prEf8KFCKv8EyG+4WrUOg7oi", "80e1000103cb6bc84218a6a3001006c801123318f6882d06086141a9c44dfbfb7e9f1cf997eb257b77c732bcf779ae750b6493aff001815dcfc814a4fb96089153b0becc4e091f2632584ee88fc01701a0dc5111f3d7b201b0a5496972275d00e503d921370ecbdebc5ac4e54572e59ca65c29ce246b438659df04633d5d0452da1b9ce729670a616b4f5050df2c7de897ca16f5762d6df93da0134d6c3d2fedb178be2fbbfa3c702673c231d5af4f1c9b2fa791a19ef3a23aee2325dc633f19ebde33f0eeec8351cfa62bbbf9339d6b7e322ba3bb5e1d31a3956475cf450984d4a274d2583d1b80e0", "80e1000103cb6bc84218a6a3cf77c0bc864411afc82ac978b1087b699bf51892b46152bcf95963dbc69f7efbb776c79a0daa3e2e7ae8a3ceda005fb29b068d099d0b0a103ae0bc9ae62b55c0c8dca25583478377f2bb310f0371a2ada32a119e96a84c796b9376a093409e21a7b16bafedbc4fffadabe5f770e895ec36b8de959819aac706aba8788ba9da2fd3f58bd43796fd51124e92117d98575cc82d302741a8be3c9234bafeb42d2c52ebd9e6edfcb1e7e01fb40131758c9d1181525b1c02e35cc34b46e0aaf1df4dc931036aaf4f9044b47058d22008395596e8000b4a7def6aa97a989e76f0c88ba939313459373a6f")]
+        public static System.Collections.Generic.IEnumerable<object[]> Test_Srtp_Protect_Unprotect_TestData()
+        {
+            var masterKeySalt = "n7z9GgmnJ4Bc2hC0prEf8KFCKv8EyG+4WrUOg7oi";
+            var rtp = "80e1000103cb6bc84218a6a3001006c801123318f6882d06086141a9c44dfbfb7e9f1cf997eb257b77c732bcf779ae750b6493aff001815dcfc814a4fb96089153b0becc4e091f2632584ee88fc01701a0dc5111f3d7b201b0a5496972275d00e503d921370ecbdebc5ac4e54572e59ca65c29ce246b438659df04633d5d0452da1b9ce729670a616b4f5050df2c7de897ca16f5762d6df93da0134d6c3d2fedb178be2fbbfa3c702673c231d5af4f1c9b2fa791a19ef3a23aee2325dc633f19ebde33f0eeec8351cfa62bbbf9339d6b7e322ba3bb5e1d31a3956475cf450984d4a274d2583d1b80e0";
+            var srtp = "80e1000103cb6bc84218a6a3cf77c0bc864411afc82ac978b1087b699bf51892b46152bcf95963dbc69f7efbb776c79a0daa3e2e7ae8a3ceda005fb29b068d099d0b0a103ae0bc9ae62b55c0c8dca25583478377f2bb310f0371a2ada32a119e96a84c796b9376a093409e21a7b16bafedbc4fffadabe5f770e895ec36b8de959819aac706aba8788ba9da2fd3f58bd43796fd51124e92117d98575cc82d302741a8be3c9234bafeb42d2c52ebd9e6edfcb1e7e01fb40131758c9d1181525b1c02e35cc34b46e0aaf1df4dc931036aaf4f9044b47058d22008395596e8000b4a7def6aa97a989e76f0c88ba939313459373a6f";
+
+            yield return new object[] { masterKeySalt, rtp, srtp, true };
+            yield return new object[] { masterKeySalt, rtp, srtp, false };
+        }
+
+        [DynamicData(nameof(Test_Srtp_Protect_Unprotect_TestData))]
         [TestMethod]
-        public void Test_Srtp_Protect_Unprotect(string masterKeySalt, string rtp, string srtp)
+        public void Test_Srtp_Protect_Unprotect(string masterKeySalt, string rtp, string srtp, bool useSharedBuffer)
         {
-            byte[] masterKeySaltBytes = Convert.FromBase64String(masterKeySalt);
+            byte[] masterKeySaltBytes = System.Convert.FromBase64String(masterKeySalt);
             byte[] rtpBytes = Convert.FromHexString(rtp);
-            byte[] srtpBytes = rtpBytes.Concat(new byte[10]).ToArray();
+            byte[] srtpProtectedBytes = new byte[rtpBytes.Length + 10];
+            ReadOnlySpan<byte> srtpUnprotectedBytes;
+
+            if (useSharedBuffer)
+            {
+                srtpUnprotectedBytes = srtpProtectedBytes.AsSpan(0, rtpBytes.Length);
+                rtpBytes.AsSpan().CopyTo(srtpProtectedBytes);
+            }
+            else
+            {
+                srtpUnprotectedBytes = rtpBytes;
+            }
 
             byte[] MKI = null;
             var keys = SrtpProtocol.CreateMasterKeys(SrtpCryptoSuites.AES_CM_128_HMAC_SHA1_80, MKI, masterKeySaltBytes);
             var context = SrtpProtocol.CreateSrtpSessionContext(keys);
-            int ret = context.ProtectRtp(srtpBytes, rtpBytes.Length, out int len);
-
-            string srtpString = Convert.ToHexString(srtpBytes.Take(len).ToArray()).ToLowerInvariant();
-            Assert.AreEqual(srtp, srtpString);
 
-            context.UnprotectRtp(srtpBytes, srtpBytes.Length, out int olen);
+            int len = context.ProtectRtp(srtpProtectedBytes.AsSpan(), srtpUnprotectedBytes);
+            var expectedSrtpBytes = Convert.FromHexString(srtp);
+            var actualSrtpBytes = srtpProtectedBytes.AsSpan(0, len).ToArray();
+            Assert.IsTrue(expectedSrtpBytes.SequenceEqual(actualSrtpBytes),
+                $"SRTP protect mismatch.\nExpected: {BitConverter.ToString(expectedSrtpBytes)}\nActual:   {BitConverter.ToString(actualSrtpBytes)}");
 
-            string rtpString = Convert.ToHexString(srtpBytes.Take(olen).ToArray()).ToLowerInvariant();
-            Assert.AreEqual(rtp, rtpString);
+            var decodeContext = SrtpProtocol.CreateSrtpSessionContext(keys);
+            Span<byte> srtpUnprotectedOut;
+            if (useSharedBuffer)
+            {
+                srtpUnprotectedOut = srtpProtectedBytes;
+            }
+            else
+            {
+                srtpUnprotectedOut = new byte[srtpProtectedBytes.Length];
+            }
+            int olen = decodeContext.UnprotectRtp(srtpUnprotectedOut, srtpProtectedBytes.AsSpan(0, len));
+            var actualUnprotected = srtpUnprotectedOut.Slice(0, olen).ToArray();
+            Assert.IsTrue(rtpBytes.SequenceEqual(actualUnprotected),
+                $"SRTP unprotect mismatch.\nExpected: {BitConverter.ToString(rtpBytes)}\nActual:   {BitConverter.ToString(actualUnprotected)}");
         }
     }
 }