Org.BouncyCastle.Crypto.Tls.CipherSuite.IsScsv C# (CSharp) Метод

        public static bool IsScsv(int cipherSuite)
        {
            switch (cipherSuite)
            {
            case TLS_EMPTY_RENEGOTIATION_INFO_SCSV:
            case TLS_FALLBACK_SCSV:
                return true;
            default:
                return false;
            }
        }
    }

        protected virtual byte[] GenerateServerHello(DtlsServerProtocol.ServerHandshakeState state)
        {
            SecurityParameters securityParameters = state.serverContext.SecurityParameters;
            MemoryStream       memoryStream       = new MemoryStream();
            ProtocolVersion    serverVersion      = state.server.GetServerVersion();

            if (!serverVersion.IsEqualOrEarlierVersionOf(state.serverContext.ClientVersion))
            {
                throw new TlsFatalAlert(80);
            }
            state.serverContext.SetServerVersion(serverVersion);
            TlsUtilities.WriteVersion(state.serverContext.ServerVersion, memoryStream);
            memoryStream.Write(securityParameters.ServerRandom, 0, securityParameters.ServerRandom.Length);
            TlsUtilities.WriteOpaque8(TlsUtilities.EmptyBytes, memoryStream);
            int selectedCipherSuite = state.server.GetSelectedCipherSuite();

            if (!Arrays.Contains(state.offeredCipherSuites, selectedCipherSuite) || selectedCipherSuite == 0 || CipherSuite.IsScsv(selectedCipherSuite) || !TlsUtilities.IsValidCipherSuiteForVersion(selectedCipherSuite, state.serverContext.ServerVersion))
            {
                throw new TlsFatalAlert(80);
            }
            DtlsProtocol.ValidateSelectedCipherSuite(selectedCipherSuite, 80);
            securityParameters.cipherSuite = selectedCipherSuite;
            byte selectedCompressionMethod = state.server.GetSelectedCompressionMethod();

            if (!Arrays.Contains(state.offeredCompressionMethods, selectedCompressionMethod))
            {
                throw new TlsFatalAlert(80);
            }
            securityParameters.compressionAlgorithm = selectedCompressionMethod;
            TlsUtilities.WriteUint16(selectedCipherSuite, memoryStream);
            TlsUtilities.WriteUint8(selectedCompressionMethod, memoryStream);
            state.serverExtensions = state.server.GetServerExtensions();
            if (state.secure_renegotiation)
            {
                byte[] extensionData = TlsUtilities.GetExtensionData(state.serverExtensions, 65281);
                bool   flag          = null == extensionData;
                if (flag)
                {
                    state.serverExtensions        = TlsExtensionsUtilities.EnsureExtensionsInitialised(state.serverExtensions);
                    state.serverExtensions[65281] = TlsProtocol.CreateRenegotiationInfo(TlsUtilities.EmptyBytes);
                }
            }
            if (securityParameters.extendedMasterSecret)
            {
                state.serverExtensions = TlsExtensionsUtilities.EnsureExtensionsInitialised(state.serverExtensions);
                TlsExtensionsUtilities.AddExtendedMasterSecretExtension(state.serverExtensions);
            }
            if (state.serverExtensions != null)
            {
                securityParameters.encryptThenMac    = TlsExtensionsUtilities.HasEncryptThenMacExtension(state.serverExtensions);
                securityParameters.maxFragmentLength = DtlsProtocol.EvaluateMaxFragmentLengthExtension(state.resumedSession, state.clientExtensions, state.serverExtensions, 80);
                securityParameters.truncatedHMac     = TlsExtensionsUtilities.HasTruncatedHMacExtension(state.serverExtensions);
                state.allowCertificateStatus         = (!state.resumedSession && TlsUtilities.HasExpectedEmptyExtensionData(state.serverExtensions, 5, 80));
                state.expectSessionTicket            = (!state.resumedSession && TlsUtilities.HasExpectedEmptyExtensionData(state.serverExtensions, 35, 80));
                TlsProtocol.WriteExtensions(memoryStream, state.serverExtensions);
            }
            securityParameters.prfAlgorithm     = TlsProtocol.GetPrfAlgorithm(state.serverContext, securityParameters.CipherSuite);
            securityParameters.verifyDataLength = 12;
            return(memoryStream.ToArray());
        }