Remove use of MKI in srtp client. (#1489)

Author: sipsorcery

src/net/DtlsSrtp/DtlsSrtpClient.cs

@@ -123,9 +123,9 @@ public DtlsSrtpClient(TlsCrypto crypto, Certificate certificateChain, Asymmetric
             {
                 SecureRandom random = new SecureRandom();
                 int[] protectionProfiles = { SrtpProtectionProfile.SRTP_AES128_CM_HMAC_SHA1_80 };
-                byte[] mki = new byte[(SrtpParameters.SRTP_AES128_CM_HMAC_SHA1_80.GetCipherKeyLength() + SrtpParameters.SRTP_AES128_CM_HMAC_SHA1_80.GetCipherSaltLength()) / 8];
-                random.NextBytes(mki); // Reusing our secure random for generating the key.
-                this.clientSrtpData = new UseSrtpData(protectionProfiles, mki);
+
+                // Note: the WebRTC spec states Master Key Identifier (MKI) is not used, see https://datatracker.ietf.org/doc/html/rfc8827#name-communications-security.
+                this.clientSrtpData = new UseSrtpData(protectionProfiles, []);
             }
             else
             {