Code:
/ DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / Security / Cryptography / DES.cs / 1 / DES.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== // // DES.cs // namespace System.Security.Cryptography { using System; [System.Runtime.InteropServices.ComVisible(true)] public abstract class DES : SymmetricAlgorithm { private static KeySizes[] s_legalBlockSizes = { new KeySizes(64, 64, 0) }; private static KeySizes[] s_legalKeySizes = { new KeySizes(64, 64, 0) }; // // protected constructors // protected DES() { KeySizeValue = 64; BlockSizeValue = 64; FeedbackSizeValue = BlockSizeValue; LegalBlockSizesValue = s_legalBlockSizes; LegalKeySizesValue = s_legalKeySizes; } // // public properties // public override byte[] Key { get { if (KeyValue == null) { // Never hand back a weak or semi-weak key do { GenerateKey(); } while (IsWeakKey(KeyValue) || IsSemiWeakKey(KeyValue)); } return (byte[]) KeyValue.Clone(); } set { if (value == null) throw new ArgumentNullException("value"); if (!ValidKeySize(value.Length * 8)) { // must convert bytes to bits throw new ArgumentException(Environment.GetResourceString("Cryptography_InvalidKeySize")); } if (IsWeakKey(value)) { throw new CryptographicException(Environment.GetResourceString("Cryptography_InvalidKey_Weak"),"DES"); } if (IsSemiWeakKey(value)) { throw new CryptographicException(Environment.GetResourceString("Cryptography_InvalidKey_SemiWeak"),"DES"); } KeyValue = (byte[]) value.Clone(); KeySizeValue = value.Length * 8; } } // // public methods // new static public DES Create() { return Create("System.Security.Cryptography.DES"); } new static public DES Create(String algName) { return (DES) CryptoConfig.CreateFromName(algName); } public static bool IsWeakKey(byte[] rgbKey) { if (!IsLegalKeySize(rgbKey)) { throw new CryptographicException(Environment.GetResourceString("Cryptography_InvalidKeySize")); } byte[] rgbOddParityKey = Utils.FixupKeyParity(rgbKey); UInt64 key = QuadWordFromBigEndian(rgbOddParityKey); if ((key == 0x0101010101010101) || (key == 0xfefefefefefefefe) || (key == 0x1f1f1f1f0e0e0e0e) || (key == 0xe0e0e0e0f1f1f1f1)) { return(true); } return(false); } public static bool IsSemiWeakKey(byte[] rgbKey) { if (!IsLegalKeySize(rgbKey)) { throw new CryptographicException(Environment.GetResourceString("Cryptography_InvalidKeySize")); } byte[] rgbOddParityKey = Utils.FixupKeyParity(rgbKey); UInt64 key = QuadWordFromBigEndian(rgbOddParityKey); if ((key == 0x01fe01fe01fe01fe) || (key == 0xfe01fe01fe01fe01) || (key == 0x1fe01fe00ef10ef1) || (key == 0xe01fe01ff10ef10e) || (key == 0x01e001e001f101f1) || (key == 0xe001e001f101f101) || (key == 0x1ffe1ffe0efe0efe) || (key == 0xfe1ffe1ffe0efe0e) || (key == 0x011f011f010e010e) || (key == 0x1f011f010e010e01) || (key == 0xe0fee0fef1fef1fe) || (key == 0xfee0fee0fef1fef1)) { return(true); } return(false); } // // private methods // private static bool IsLegalKeySize(byte[] rgbKey) { if (rgbKey != null && rgbKey.Length == 8) return(true); return(false); } private static UInt64 QuadWordFromBigEndian(byte[] block) { UInt64 x; x = ( (((UInt64)block[0]) << 56) | (((UInt64)block[1]) << 48) | (((UInt64)block[2]) << 40) | (((UInt64)block[3]) << 32) | (((UInt64)block[4]) << 24) | (((UInt64)block[5]) << 16) | (((UInt64)block[6]) << 8) | ((UInt64)block[7]) ); return(x); } } }
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- Expander.cs
- DCSafeHandle.cs
- DiagnosticStrings.cs
- TextRenderingModeValidation.cs
- WindowsFormsHostAutomationPeer.cs
- XmlWriter.cs
- SwitchLevelAttribute.cs
- MetadataSource.cs
- StringAnimationBase.cs
- RIPEMD160Managed.cs
- XmlDesignerDataSourceView.cs
- AppDomainShutdownMonitor.cs
- WindowsHyperlink.cs
- XmlSortKey.cs
- Object.cs
- DataSourceProvider.cs
- OptimizedTemplateContentHelper.cs
- CompositionTarget.cs
- ListSourceHelper.cs
- GiveFeedbackEvent.cs
- NewExpression.cs
- KeyFrames.cs
- ExpressionBuilder.cs
- Compress.cs
- ResourcePool.cs
- VerificationAttribute.cs
- AssemblyHash.cs
- COM2IManagedPerPropertyBrowsingHandler.cs
- Message.cs
- DataGridColumnReorderingEventArgs.cs
- sapiproxy.cs
- BaseValidator.cs
- BrowserCapabilitiesCompiler.cs
- DbReferenceCollection.cs
- RenderContext.cs
- LogEntryUtils.cs
- BuildDependencySet.cs
- UserControl.cs
- ShaderEffect.cs
- ExpressionDumper.cs
- Internal.cs
- TemplateInstanceAttribute.cs
- AnimationClock.cs
- RemotingException.cs
- StylusButtonEventArgs.cs
- CoreSwitches.cs
- StylusPointProperties.cs
- SingleObjectCollection.cs
- TextRangeEditTables.cs
- DataRowView.cs
- RenderContext.cs
- DateTimeFormatInfoScanner.cs
- SQLRoleProvider.cs
- TypeInitializationException.cs
- AspNetHostingPermission.cs
- BoundsDrawingContextWalker.cs
- SafeProcessHandle.cs
- SuppressIldasmAttribute.cs
- Setter.cs
- LayoutEvent.cs
- CompilerGlobalScopeAttribute.cs
- Cursor.cs
- AttributeUsageAttribute.cs
- NativeRightsManagementAPIsStructures.cs
- SelectManyQueryOperator.cs
- DataGridTable.cs
- RenderOptions.cs
- PackageDocument.cs
- PrintEvent.cs
- ItemChangedEventArgs.cs
- TextRunTypographyProperties.cs
- HtmlElementEventArgs.cs
- DropSource.cs
- PipelineModuleStepContainer.cs
- FrameworkContentElement.cs
- ValidateNames.cs
- _SslState.cs
- Helpers.cs
- XXXInfos.cs
- ReadOnlyState.cs
- FlowDocumentFormatter.cs
- DataGridViewAccessibleObject.cs
- DoubleUtil.cs
- EdmProperty.cs
- RecordsAffectedEventArgs.cs
- CallContext.cs
- ClockGroup.cs
- DetailsViewInsertedEventArgs.cs
- PropertyRef.cs
- CornerRadius.cs
- SqlDataAdapter.cs
- ImageCollectionEditor.cs
- HtmlInputCheckBox.cs
- XmlTypeMapping.cs
- CharKeyFrameCollection.cs
- SessionEndedEventArgs.cs
- EventWaitHandle.cs
- WindowsFormsHostAutomationPeer.cs
- ButtonStandardAdapter.cs
- EntityDataSourceDesigner.cs