Code:
/ DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / Security / Cryptography / DESCryptoServiceProvider.cs / 1 / DESCryptoServiceProvider.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== // // DESCryptoServiceProvider.cs // namespace System.Security.Cryptography { [System.Runtime.InteropServices.ComVisible(true)] public sealed class DESCryptoServiceProvider : DES { // // public constructors // public DESCryptoServiceProvider () { if (!Utils.HasAlgorithm(Constants.CALG_DES, 0)) throw new CryptographicException(Environment.GetResourceString("Cryptography_CSP_AlgorithmNotAvailable")); // Since the CSP only supports a CFB feedback of 8, make that the default FeedbackSizeValue = 8; } // // public methods // public override ICryptoTransform CreateEncryptor (byte[] rgbKey, byte[] rgbIV) { if (IsWeakKey(rgbKey)) throw new CryptographicException(Environment.GetResourceString("Cryptography_InvalidKey_Weak"),"DES"); if (IsSemiWeakKey(rgbKey)) throw new CryptographicException(Environment.GetResourceString("Cryptography_InvalidKey_SemiWeak"),"DES"); return _NewEncryptor(rgbKey, ModeValue, rgbIV, FeedbackSizeValue, CryptoAPITransformMode.Encrypt); } public override ICryptoTransform CreateDecryptor (byte[] rgbKey, byte[] rgbIV) { if (IsWeakKey(rgbKey)) throw new CryptographicException(Environment.GetResourceString("Cryptography_InvalidKey_Weak"),"DES"); if (IsSemiWeakKey(rgbKey)) throw new CryptographicException(Environment.GetResourceString("Cryptography_InvalidKey_SemiWeak"),"DES"); return _NewEncryptor(rgbKey, ModeValue, rgbIV, FeedbackSizeValue, CryptoAPITransformMode.Decrypt); } public override void GenerateKey () { KeyValue = new byte[8]; Utils.StaticRandomNumberGenerator.GetBytes(KeyValue); // Never hand back a weak or semi-weak key while (DES.IsWeakKey(KeyValue) || DES.IsSemiWeakKey(KeyValue)) { Utils.StaticRandomNumberGenerator.GetBytes(KeyValue); } } public override void GenerateIV () { IVValue = new byte[8]; Utils.StaticRandomNumberGenerator.GetBytes(IVValue); } // // private methods // private ICryptoTransform _NewEncryptor (byte[] rgbKey, CipherMode mode, byte[] rgbIV, int feedbackSize, CryptoAPITransformMode encryptMode) { int cArgs = 0; int[] rgArgIds = new int[10]; Object[] rgArgValues = new Object[10]; // Check for bad values // 1) we don't support OFB mode in DESCryptoServiceProvider if (mode == CipherMode.OFB) throw new CryptographicException(Environment.GetResourceString("Cryptography_CSP_OFBNotSupported")); // 2) we only support CFB with a feedback size of 8 bits if ((mode == CipherMode.CFB) && (feedbackSize != 8)) throw new CryptographicException(Environment.GetResourceString("Cryptography_CSP_CFBSizeNotSupported")); // Build the key if one does not already exist if (rgbKey == null) { rgbKey = new byte[8]; Utils.StaticRandomNumberGenerator.GetBytes(rgbKey); } // Set the mode for the encryptor (defaults to CBC) if (mode != CipherMode.CBC) { rgArgIds[cArgs] = Constants.KP_MODE; rgArgValues[cArgs] = mode; cArgs += 1; } // If not ECB mode -- pass in an IV if (mode != CipherMode.ECB) { if (rgbIV == null) { rgbIV = new byte[8]; Utils.StaticRandomNumberGenerator.GetBytes(rgbIV); } // // We truncate IV's that are longer than the block size to 8 bytes : this is // done to maintain backward compatibility with the behavior shipped in V1.x. // The call to set the IV in CryptoAPI will ignore any bytes after the first 8 // bytes. We'll still reject IV's that are shorter than the block size though. // if (rgbIV.Length < 8) throw new CryptographicException(Environment.GetResourceString("Cryptography_InvalidIVSize")); rgArgIds[cArgs] = Constants.KP_IV; rgArgValues[cArgs] = rgbIV; cArgs += 1; } // If doing OFB or CFB, then we need to set the feed back loop size if ((mode == CipherMode.OFB) || (mode == CipherMode.CFB)) { rgArgIds[cArgs] = Constants.KP_MODE_BITS; rgArgValues[cArgs] = feedbackSize; cArgs += 1; } // Create the encryptpr/decryptor object return new CryptoAPITransform(Constants.CALG_DES, cArgs, rgArgIds, rgArgValues, rgbKey, PaddingValue, mode, BlockSizeValue, feedbackSize, false, encryptMode); } } }
Link Menu
![Network programming in C#, Network Programming in VB.NET, Network Programming in .NET](/images/book.jpg)
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- Version.cs
- HttpSessionStateBase.cs
- EditBehavior.cs
- ConfigurationStrings.cs
- LinqDataSourceInsertEventArgs.cs
- TableCellAutomationPeer.cs
- CollectionType.cs
- ContentType.cs
- BooleanAnimationUsingKeyFrames.cs
- _DisconnectOverlappedAsyncResult.cs
- ReadOnlyMetadataCollection.cs
- UIElementAutomationPeer.cs
- ProjectionAnalyzer.cs
- ObjectListGeneralPage.cs
- DirectoryInfo.cs
- TableCellCollection.cs
- ProtocolsConfiguration.cs
- JsonReader.cs
- TableParagraph.cs
- ErrorFormatterPage.cs
- PropertyItemInternal.cs
- TypeBuilderInstantiation.cs
- StrokeCollection2.cs
- HttpWebRequestElement.cs
- bidPrivateBase.cs
- SharedDp.cs
- XmlAttribute.cs
- DynamicResourceExtensionConverter.cs
- DataGridCellClipboardEventArgs.cs
- WindowsIPAddress.cs
- ColumnResizeUndoUnit.cs
- CheckBoxDesigner.cs
- VoiceChangeEventArgs.cs
- ResourcePermissionBaseEntry.cs
- DescendentsWalker.cs
- AlignmentXValidation.cs
- HttpCookiesSection.cs
- RestHandlerFactory.cs
- ObjectContextServiceProvider.cs
- TypographyProperties.cs
- DefaultTraceListener.cs
- SamlConditions.cs
- Vars.cs
- Expressions.cs
- CroppedBitmap.cs
- StrokeCollectionDefaultValueFactory.cs
- TextFormatterImp.cs
- RadioButton.cs
- EncodingTable.cs
- GridToolTip.cs
- ResourceAssociationSetEnd.cs
- NullableIntAverageAggregationOperator.cs
- Int32CollectionValueSerializer.cs
- SafeCoTaskMem.cs
- SendActivityDesignerTheme.cs
- BuildResultCache.cs
- SelectorItemAutomationPeer.cs
- PersonalizationState.cs
- RegisteredDisposeScript.cs
- _NestedMultipleAsyncResult.cs
- ObjectQueryExecutionPlan.cs
- SslStreamSecurityUpgradeProvider.cs
- NameValuePair.cs
- TableHeaderCell.cs
- TemplateField.cs
- HttpCapabilitiesBase.cs
- IDispatchConstantAttribute.cs
- URLIdentityPermission.cs
- PropertyMappingExceptionEventArgs.cs
- MultiSelectRootGridEntry.cs
- Decoder.cs
- DataGridViewCellPaintingEventArgs.cs
- BindingExpressionBase.cs
- RoutedEventArgs.cs
- ProtectedConfiguration.cs
- StylusPlugInCollection.cs
- XmlNotation.cs
- SortAction.cs
- HttpException.cs
- DocumentSequenceHighlightLayer.cs
- BulletedListEventArgs.cs
- LocalIdKeyIdentifierClause.cs
- UInt32Converter.cs
- CurrentChangingEventManager.cs
- LabelAutomationPeer.cs
- WebPartUtil.cs
- TextElementEnumerator.cs
- Timer.cs
- SpeechAudioFormatInfo.cs
- DataGridViewCellStateChangedEventArgs.cs
- DataColumnCollection.cs
- MarkedHighlightComponent.cs
- StringAttributeCollection.cs
- FixedDSBuilder.cs
- Inline.cs
- RegistrationServices.cs
- ProfileInfo.cs
- AnnotationHighlightLayer.cs
- ExtenderControl.cs
- AuthStoreRoleProvider.cs