public byte[] GetOutgoingBlob(byte[] incomingBlob, ChannelBinding channelbinding, ExtendedProtectionPolicy protectionPolicy)
        {
            ThrowIfDisposed();
            int statusCode = 0;

            // use the confidentiality option to ensure we can encrypt messages
            SspiContextFlags requestedFlags = SspiContextFlags.Confidentiality
                                              | SspiContextFlags.ReplayDetect
                                              | SspiContextFlags.SequenceDetect;

            if (this.doMutualAuth)
            {
                requestedFlags |= SspiContextFlags.MutualAuth;
            }

            if (this.impersonationLevel == TokenImpersonationLevel.Delegation)
            {
                requestedFlags |= SspiContextFlags.Delegate;
            }
            else if (this.isServer == false && this.impersonationLevel == TokenImpersonationLevel.Identification)
            {
                requestedFlags |= SspiContextFlags.InitIdentify;
            }
            else if (this.isServer == false && this.impersonationLevel == TokenImpersonationLevel.Anonymous)
            {
                requestedFlags |= SspiContextFlags.InitAnonymous;
            }

            ExtendedProtectionPolicyHelper policyHelper = new ExtendedProtectionPolicyHelper(channelbinding, protectionPolicy);

            if (isServer)
            {
                if (policyHelper.PolicyEnforcement == PolicyEnforcement.Always && policyHelper.ChannelBinding == null && policyHelper.ProtectionScenario != ProtectionScenario.TrustedProxy)
                {
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new SecurityTokenException(SR.GetString(SR.SecurityChannelBindingMissing)));
                }

                if (policyHelper.PolicyEnforcement == PolicyEnforcement.WhenSupported)
                {
                    requestedFlags |= SspiContextFlags.ChannelBindingAllowMissingBindings;
                }

                if (policyHelper.ProtectionScenario == ProtectionScenario.TrustedProxy)
                {
                    requestedFlags |= SspiContextFlags.ChannelBindingProxyBindings;
                }
            }

            List <SecurityBuffer> list = new List <SecurityBuffer>(2);

            if (incomingBlob != null)
            {
                list.Add(new SecurityBuffer(incomingBlob, BufferType.Token));
            }

            // when deciding if the channel binding should be added to the security buffer
            // it is necessary to differentiate between  client and server.
            // Server rules were added to policyHelper as they are shared with Kerb and I want them consistent
            // Client adds if not null.
            if (this.isServer)
            {
                if (policyHelper.ShouldAddChannelBindingToASC())
                {
                    list.Add(new SecurityBuffer(policyHelper.ChannelBinding));
                }
            }
            else
            {
                if (policyHelper.ChannelBinding != null)
                {
                    list.Add(new SecurityBuffer(policyHelper.ChannelBinding));
                }
            }

            SecurityBuffer[] inSecurityBuffer = null;
            if (list.Count > 0)
            {
                inSecurityBuffer = list.ToArray();
            }

            SecurityBuffer outSecurityBuffer = new SecurityBuffer(this.tokenSize, BufferType.Token);

            if (!this.isServer)
            {
                //client session
                statusCode = SspiWrapper.InitializeSecurityContext(this.credentialsHandle,
                                                                   ref this.securityContext,
                                                                   this.servicePrincipalName,
                                                                   requestedFlags,
                                                                   Endianness.Network,
                                                                   inSecurityBuffer,
                                                                   outSecurityBuffer,
                                                                   ref this.contextFlags);
            }
            else
            {
                // server session
                //This check is to save an unnecessary ASC call.
                bool             isServerSecurityContextNull = this.securityContext == null;
                SspiContextFlags serverContextFlags          = this.contextFlags;

                statusCode = SspiWrapper.AcceptSecurityContext(this.credentialsHandle,
                                                               ref this.securityContext,
                                                               requestedFlags,
                                                               Endianness.Network,
                                                               inSecurityBuffer,
                                                               outSecurityBuffer,
                                                               ref this.contextFlags);

                if (statusCode == (int)SecurityStatus.InvalidToken && !isServerSecurityContextNull)
                {
                    // Call again into ASC after deleting the Securitycontext. If this securitycontext is not deleted
                    // then when the client sends NTLM blob the service will treat it as Nego2blob and will fail to authenticate the client.
                    this.contextFlags = serverContextFlags;
                    CloseContext();
                    statusCode = SspiWrapper.AcceptSecurityContext(this.credentialsHandle,
                                                                   ref this.securityContext,
                                                                   requestedFlags,
                                                                   Endianness.Network,
                                                                   inSecurityBuffer,
                                                                   outSecurityBuffer,
                                                                   ref this.contextFlags);
                }
            }

            if (DiagnosticUtility.ShouldTraceInformation)
            {
                IMD.SecurityTraceRecordHelper.TraceChannelBindingInformation(policyHelper, this.isServer, channelbinding);
            }

            if ((statusCode & unchecked ((int)0x80000000)) != 0)
            {
                if (!this.isServer &&
                    this.interactiveNegoLogonEnabled &&
                    SecurityUtils.IsOSGreaterThanOrEqualToWin7() &&
                    SspiWrapper.IsSspiPromptingNeeded((uint)statusCode) &&
                    SspiWrapper.IsNegotiateExPackagePresent())
                {
                    // If we have prompted enough number of times (DefaultMaxPromptAttempts) with wrong credentials, then we do not prompt again and throw.
                    if (MaxPromptAttempts >= DefaultMaxPromptAttempts)
                    {
                        throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new Win32Exception(statusCode, SR.GetString(SR.InvalidClientCredentials)));
                    }

                    IntPtr ppAuthIdentity = IntPtr.Zero;
                    uint   errorCode      = SspiWrapper.SspiPromptForCredential(this.servicePrincipalName, this.clientPackageName, out ppAuthIdentity, ref this.saveClientCredentialsOnSspiUi);
                    if (errorCode == (uint)CredentialStatus.Success)
                    {
                        IntPtr ppNewAuthIdentity = IntPtr.Zero;

                        if (!this.allowNtlm)
                        {
                            // When Ntlm is  explicitly disabled we don't want the collected
                            //creds from the Kerb/NTLM tile to be used for NTLM auth.

                            uint status = UnsafeNativeMethods.SspiExcludePackage(ppAuthIdentity, "NTLM", out ppNewAuthIdentity);
                        }
                        else
                        {
                            ppNewAuthIdentity = ppAuthIdentity;
                        }

                        this.credentialsHandle = SspiWrapper.AcquireCredentialsHandle(this.clientPackageName, CredentialUse.Outbound, ref ppNewAuthIdentity);

                        if (IntPtr.Zero != ppNewAuthIdentity)
                        {
                            UnsafeNativeMethods.SspiFreeAuthIdentity(ppNewAuthIdentity);
                        }

                        CloseContext();

                        MaxPromptAttempts++;
                        return(this.GetOutgoingBlob(null, channelbinding, protectionPolicy));
                    }
                    else
                    {
                        // Call into SspiPromptForCredential had an error. Time to throw.
                        if (IntPtr.Zero != ppAuthIdentity)
                        {
                            UnsafeNativeMethods.SspiFreeAuthIdentity(ppAuthIdentity);
                        }

                        CloseContext();
                        this.isCompleted = true;
                        throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new Win32Exception((int)errorCode, SR.GetString(SR.SspiErrorOrInvalidClientCredentials)));
                    }
                }

                CloseContext();
                this.isCompleted = true;
                if (!this.isServer && (statusCode == (int)SecurityStatus.TargetUnknown ||
                                       statusCode == (int)SecurityStatus.WrongPrincipal))
                {
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new Win32Exception(statusCode, SR.GetString(SR.IncorrectSpnOrUpnSpecified, this.servicePrincipalName)));
                }
                else
                {
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new Win32Exception(statusCode, SR.GetString(SR.InvalidSspiNegotiation)));
                }
            }

            if (DiagnosticUtility.ShouldTraceInformation)
            {
                if (this.isServer)
                {
                    SecurityTraceRecordHelper.TraceServiceOutgoingSpnego(this);
                }
                else
                {
                    SecurityTraceRecordHelper.TraceClientOutgoingSpnego(this);
                }
            }

            if (statusCode == (int)SecurityStatus.OK)
            {
                // we're done
                this.isCompleted = true;

                // These must all be true to check service binding
                // 1. we are the service (listener)
                // 2. caller is not anonymous
                // 3. protocol is not Kerberos
                // 4. policy is set to check service binding
                //
                if (isServer && ((this.contextFlags & SspiContextFlags.AcceptAnonymous) == 0) && (string.Compare(this.ProtocolName, NegotiationInfoClass.Kerberos, StringComparison.OrdinalIgnoreCase) != 0) && policyHelper.ShouldCheckServiceBinding)
                {
                    // in the server case the servicePrincipalName is the defaultServiceBinding

                    if (DiagnosticUtility.ShouldTraceInformation)
                    {
                        string serviceBindingNameSentByClient;
                        SspiWrapper.QuerySpecifiedTarget(securityContext, out serviceBindingNameSentByClient);
                        IMD.SecurityTraceRecordHelper.TraceServiceNameBindingOnServer(serviceBindingNameSentByClient, this.servicePrincipalName, policyHelper.ServiceNameCollection);
                    }

                    policyHelper.CheckServiceBinding(this.securityContext, this.servicePrincipalName);
                }
            }
            else
            {
                // we need to continue
            }

            return(outSecurityBuffer.token);
        }