Org.BouncyCastle.Crypto.Tls.DtlsClientProtocol.GenerateClientHello C# (CSharp) Метод

        protected virtual byte[] GenerateClientHello(ClientHandshakeState state, TlsClient client)
        {
            MemoryStream buf = new MemoryStream();

            ProtocolVersion client_version = client.ClientVersion;
            if (!client_version.IsDtls)
                throw new TlsFatalAlert(AlertDescription.internal_error);

            TlsClientContextImpl context = state.clientContext;

            context.SetClientVersion(client_version);
            TlsUtilities.WriteVersion(client_version, buf);

            SecurityParameters securityParameters = context.SecurityParameters;
            buf.Write(securityParameters.ClientRandom, 0, securityParameters.ClientRandom.Length);

            // Session ID
            byte[] session_id = TlsUtilities.EmptyBytes;
            if (state.tlsSession != null)
            {
                session_id = state.tlsSession.SessionID;
                if (session_id == null || session_id.Length > 32)
                {
                    session_id = TlsUtilities.EmptyBytes;
                }
            }
            TlsUtilities.WriteOpaque8(session_id, buf);

            // Cookie
            TlsUtilities.WriteOpaque8(TlsUtilities.EmptyBytes, buf);

            bool fallback = client.IsFallback;

            /*
             * Cipher suites
             */
            state.offeredCipherSuites = client.GetCipherSuites();

            // Integer -> byte[]
            state.clientExtensions = client.GetClientExtensions();

            // Cipher Suites (and SCSV)
            {
                /*
                 * RFC 5746 3.4. The client MUST include either an empty "renegotiation_info" extension,
                 * or the TLS_EMPTY_RENEGOTIATION_INFO_SCSV signaling cipher suite value in the
                 * ClientHello. Including both is NOT RECOMMENDED.
                 */
                byte[] renegExtData = TlsUtilities.GetExtensionData(state.clientExtensions, ExtensionType.renegotiation_info);
                bool noRenegExt = (null == renegExtData);

                bool noRenegSCSV = !Arrays.Contains(state.offeredCipherSuites, CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV);

                if (noRenegExt && noRenegSCSV)
                {
                    // TODO Consider whether to default to a client extension instead
                    state.offeredCipherSuites = Arrays.Append(state.offeredCipherSuites, CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV);
                }

                /*
                 * RFC 7507 4. If a client sends a ClientHello.client_version containing a lower value
                 * than the latest (highest-valued) version supported by the client, it SHOULD include
                 * the TLS_FALLBACK_SCSV cipher suite value in ClientHello.cipher_suites [..]. (The
                 * client SHOULD put TLS_FALLBACK_SCSV after all cipher suites that it actually intends
                 * to negotiate.)
                 */
                if (fallback && !Arrays.Contains(state.offeredCipherSuites, CipherSuite.TLS_FALLBACK_SCSV))
                {
                    state.offeredCipherSuites = Arrays.Append(state.offeredCipherSuites, CipherSuite.TLS_FALLBACK_SCSV);
                }

                TlsUtilities.WriteUint16ArrayWithUint16Length(state.offeredCipherSuites, buf);
            }

            // TODO Add support for compression
            // Compression methods
            // state.offeredCompressionMethods = client.getCompressionMethods();
            state.offeredCompressionMethods = new byte[]{ CompressionMethod.cls_null };

            TlsUtilities.WriteUint8ArrayWithUint8Length(state.offeredCompressionMethods, buf);

            // Extensions
            if (state.clientExtensions != null)
            {
                TlsProtocol.WriteExtensions(buf, state.clientExtensions);
            }

            return buf.ToArray();
        }