public void Process(TimeSpan timeout, ChannelBinding channelBinding, ExtendedProtectionPolicy extendedProtectionPolicy)
        {
            Fx.Assert(ReaderQuotas != null, "Reader quotas must be set before processing");
            MessageProtectionOrder actualProtectionOrder = _protectionOrder;
            bool wasProtectionOrderDowngraded            = false;

            if (_protectionOrder == MessageProtectionOrder.SignBeforeEncryptAndEncryptSignature)
            {
                throw ExceptionHelper.PlatformNotSupported(); // No support for message encryption
            }

            _channelBinding           = channelBinding;
            _extendedProtectionPolicy = extendedProtectionPolicy;
            _orderTracker.SetRequiredProtectionOrder(actualProtectionOrder);

            SetProcessingStarted();
            _timeoutHelper = new TimeoutHelper(timeout);
            Message        = SecurityVerifiedMessage = new SecurityVerifiedMessage(Message, this);
            XmlDictionaryReader reader = CreateSecurityHeaderReader();

            reader.MoveToStartElement();
            if (reader.IsEmptyElement)
            {
                throw TraceUtility.ThrowHelperError(new MessageSecurityException(SR.SecurityHeaderIsEmpty), Message);
            }
            if (RequireMessageProtection)
            {
                _securityElementAttributes = XmlAttributeHolder.ReadAttributes(reader);
            }
            else
            {
                _securityElementAttributes = XmlAttributeHolder.emptyArray;
            }
            reader.ReadStartElement();

            if (_primaryTokenParameters != null)
            {
                _primaryTokenTracker = new TokenTracker(null, _outOfBandPrimaryToken, _allowFirstTokenMismatch);
            }
            // universalTokenResolver is used for resolving tokens
            _universalTokenResolver = new SecurityHeaderTokenResolver(this);
            // primary token resolver is used for resolving primary signature and decryption
            _primaryTokenResolver = new SecurityHeaderTokenResolver(this);
            if (_outOfBandPrimaryToken != null)
            {
                _universalTokenResolver.Add(_outOfBandPrimaryToken, SecurityTokenReferenceStyle.External, _primaryTokenParameters);
                _primaryTokenResolver.Add(_outOfBandPrimaryToken, SecurityTokenReferenceStyle.External, _primaryTokenParameters);
            }
            else if (_outOfBandPrimaryTokenCollection != null)
            {
                for (int i = 0; i < _outOfBandPrimaryTokenCollection.Count; ++i)
                {
                    _universalTokenResolver.Add(_outOfBandPrimaryTokenCollection[i], SecurityTokenReferenceStyle.External, _primaryTokenParameters);
                    _primaryTokenResolver.Add(_outOfBandPrimaryTokenCollection[i], SecurityTokenReferenceStyle.External, _primaryTokenParameters);
                }
            }
            if (_wrappingToken != null)
            {
                _universalTokenResolver.ExpectedWrapper = _wrappingToken;
                _universalTokenResolver.ExpectedWrapperTokenParameters = _wrappingTokenParameters;
                _primaryTokenResolver.ExpectedWrapper = _wrappingToken;
                _primaryTokenResolver.ExpectedWrapperTokenParameters = _wrappingTokenParameters;
            }

            if (_outOfBandTokenResolver == null)
            {
                CombinedUniversalTokenResolver = _universalTokenResolver;
                _combinedPrimaryTokenResolver  = _primaryTokenResolver;
            }
            else
            {
                CombinedUniversalTokenResolver = new AggregateSecurityHeaderTokenResolver(_universalTokenResolver, _outOfBandTokenResolver);
                _combinedPrimaryTokenResolver  = new AggregateSecurityHeaderTokenResolver(_primaryTokenResolver, _outOfBandTokenResolver);
            }

            _allowedAuthenticators = new List <SecurityTokenAuthenticator>();
            if (_primaryTokenAuthenticator != null)
            {
                _allowedAuthenticators.Add(_primaryTokenAuthenticator);
            }
            if (DerivedTokenAuthenticator != null)
            {
                _allowedAuthenticators.Add(DerivedTokenAuthenticator);
            }
            _pendingSupportingTokenAuthenticator = null;
            int numSupportingTokensRequiringDerivation = 0;

            if (_supportingTokenAuthenticators != null && _supportingTokenAuthenticators.Count > 0)
            {
                _supportingTokenTrackers = new List <TokenTracker>(_supportingTokenAuthenticators.Count);
                for (int i = 0; i < _supportingTokenAuthenticators.Count; ++i)
                {
                    SupportingTokenAuthenticatorSpecification spec = _supportingTokenAuthenticators[i];
                    switch (spec.SecurityTokenAttachmentMode)
                    {
                    case SecurityTokenAttachmentMode.Endorsing:
                        _hasEndorsingOrSignedEndorsingSupportingTokens = true;
                        break;

                    case SecurityTokenAttachmentMode.Signed:
                        break;

                    case SecurityTokenAttachmentMode.SignedEndorsing:
                        _hasEndorsingOrSignedEndorsingSupportingTokens = true;
                        break;

                    case SecurityTokenAttachmentMode.SignedEncrypted:
                        break;
                    }

                    if ((_primaryTokenAuthenticator != null) && (_primaryTokenAuthenticator.GetType().Equals(spec.TokenAuthenticator.GetType())))
                    {
                        _pendingSupportingTokenAuthenticator = spec.TokenAuthenticator;
                    }
                    else
                    {
                        _allowedAuthenticators.Add(spec.TokenAuthenticator);
                    }
                    if (spec.TokenParameters.RequireDerivedKeys && !spec.TokenParameters.HasAsymmetricKey &&
                        (spec.SecurityTokenAttachmentMode == SecurityTokenAttachmentMode.Endorsing || spec.SecurityTokenAttachmentMode == SecurityTokenAttachmentMode.SignedEndorsing))
                    {
                        ++numSupportingTokensRequiringDerivation;
                    }
                    _supportingTokenTrackers.Add(new TokenTracker(spec));
                }
            }

            if (DerivedTokenAuthenticator != null)
            {
                // we expect key derivation. Compute quotas for derived keys
                int maxKeyDerivationLengthInBits = AlgorithmSuite.DefaultEncryptionKeyDerivationLength >= AlgorithmSuite.DefaultSignatureKeyDerivationLength ?
                                                   AlgorithmSuite.DefaultEncryptionKeyDerivationLength : AlgorithmSuite.DefaultSignatureKeyDerivationLength;
                MaxDerivedKeyLength = maxKeyDerivationLengthInBits / 8;
                // the upper bound of derived keys is (1 for primary signature + 1 for encryption + supporting token signatures requiring derivation)*2
                // the multiplication by 2 is to take care of interop scenarios that may arise that require more derived keys than the lower bound.
                _maxDerivedKeys = (1 + 1 + numSupportingTokensRequiringDerivation) * 2;
            }

            SecurityHeaderElementInferenceEngine engine = SecurityHeaderElementInferenceEngine.GetInferenceEngine(Layout);

            engine.ExecuteProcessingPasses(this, reader);
            if (RequireMessageProtection)
            {
                throw ExceptionHelper.PlatformNotSupported();
            }

            EnsureDecryptionComplete();

            _signatureTracker.SetDerivationSourceIfRequired();
            _encryptionTracker.SetDerivationSourceIfRequired();
            if (EncryptionToken != null)
            {
                throw ExceptionHelper.PlatformNotSupported();
            }

            // ensure that the primary signature was signed with derived keys if required
            if (EnforceDerivedKeyRequirement)
            {
                if (SignatureToken != null)
                {
                    if (_primaryTokenParameters != null)
                    {
                        if (_primaryTokenParameters.RequireDerivedKeys && !_primaryTokenParameters.HasAsymmetricKey && !_primaryTokenTracker.IsDerivedFrom)
                        {
                            throw DiagnosticUtility.ExceptionUtility.ThrowHelperWarning(new MessageSecurityException(SR.Format(SR.PrimarySignatureWasNotSignedByDerivedKey, _primaryTokenParameters)));
                        }
                    }
                    else if (_wrappingTokenParameters != null && _wrappingTokenParameters.RequireDerivedKeys)
                    {
                        if (!_signatureTracker.IsDerivedToken)
                        {
                            throw DiagnosticUtility.ExceptionUtility.ThrowHelperWarning(new MessageSecurityException(SR.Format(SR.PrimarySignatureWasNotSignedByDerivedWrappedKey, _wrappingTokenParameters)));
                        }
                    }
                }

                // verify that the encryption is using key derivation
                if (EncryptionToken != null)
                {
                    throw ExceptionHelper.PlatformNotSupported();
                }
            }

            if (wasProtectionOrderDowngraded && (BasicSupportingTokens != null) && (BasicSupportingTokens.Count > 0))
            {
                throw ExceptionHelper.PlatformNotSupported();
            }

            // verify all supporting token parameters have their requirements met
            if (_supportingTokenTrackers != null && _supportingTokenTrackers.Count > 0)
            {
                throw ExceptionHelper.PlatformNotSupported();
            }

            if (_replayDetectionEnabled)
            {
                throw ExceptionHelper.PlatformNotSupported();
            }

            if (ExpectSignatureConfirmation)
            {
                throw ExceptionHelper.PlatformNotSupported();
            }

            MarkHeaderAsUnderstood();
        }