Code:
/ FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / Security / Cryptography / SymmetricAlgorithm.cs / 1 / SymmetricAlgorithm.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== // // SymmetricAlgorithm.cs // namespace System.Security.Cryptography { [System.Runtime.InteropServices.ComVisible(true)] public abstract class SymmetricAlgorithm : IDisposable { protected int BlockSizeValue; protected int FeedbackSizeValue; protected byte[] IVValue; protected byte[] KeyValue; protected KeySizes[] LegalBlockSizesValue; protected KeySizes[] LegalKeySizesValue; protected int KeySizeValue; protected CipherMode ModeValue; protected PaddingMode PaddingValue; // // protected constructors // protected SymmetricAlgorithm() { // Default to cipher block chaining (CipherMode.CBC) and // PKCS-style padding (pad n bytes with value n) ModeValue = CipherMode.CBC; PaddingValue = PaddingMode.PKCS7; } // SymmetricAlgorithm implements IDisposable ///void IDisposable.Dispose() { Dispose(true); GC.SuppressFinalize(this); } public void Clear() { ((IDisposable) this).Dispose(); } protected virtual void Dispose(bool disposing) { if (disposing) { // Note: we always want to zeroize the sensitive key material if (KeyValue != null) { Array.Clear(KeyValue, 0, KeyValue.Length); KeyValue = null; } if (IVValue != null) { Array.Clear(IVValue, 0, IVValue.Length); IVValue = null; } } } // // public properties // public virtual int BlockSize { get { return BlockSizeValue; } set { int i; int j; for (i=0; i BlockSizeValue || (value % 8) != 0) throw new CryptographicException(Environment.GetResourceString("Cryptography_InvalidFeedbackSize")); FeedbackSizeValue = value; } } public virtual byte[] IV { get { if (IVValue == null) GenerateIV(); return (byte[]) IVValue.Clone(); } set { if (value == null) throw new ArgumentNullException("value"); if (value.Length != BlockSizeValue / 8) throw new CryptographicException(Environment.GetResourceString("Cryptography_InvalidIVSize")); IVValue = (byte[]) value.Clone(); } } public virtual byte[] Key { get { if (KeyValue == null) GenerateKey(); return (byte[]) KeyValue.Clone(); } set { if (value == null) throw new ArgumentNullException("value"); if (!ValidKeySize(value.Length * 8)) throw new CryptographicException(Environment.GetResourceString("Cryptography_InvalidKeySize")); // must convert bytes to bits KeyValue = (byte[]) value.Clone(); KeySizeValue = value.Length * 8; } } public virtual KeySizes[] LegalBlockSizes { get { return (KeySizes[]) LegalBlockSizesValue.Clone(); } } public virtual KeySizes[] LegalKeySizes { get { return (KeySizes[]) LegalKeySizesValue.Clone(); } } public virtual int KeySize { get { return KeySizeValue; } set { if (!ValidKeySize(value)) throw new CryptographicException(Environment.GetResourceString("Cryptography_InvalidKeySize")); KeySizeValue = value; KeyValue = null; } } public virtual CipherMode Mode { get { return ModeValue; } set { if ((value < CipherMode.CBC) || (CipherMode.CFB < value)) throw new CryptographicException(Environment.GetResourceString("Cryptography_InvalidCipherMode")); ModeValue = value; } } public virtual PaddingMode Padding { get { return PaddingValue; } set { if ((value < PaddingMode.None) || (PaddingMode.ISO10126 < value)) throw new CryptographicException(Environment.GetResourceString("Cryptography_InvalidPaddingMode")); PaddingValue = value; } } // // public methods // // The following method takes a bit length input and returns whether that length is a valid size // according to LegalKeySizes public bool ValidKeySize(int bitLength) { KeySizes[] validSizes = this.LegalKeySizes; int i,j; if (validSizes == null) return false; for (i=0; i< validSizes.Length; i++) { if (validSizes[i].SkipSize == 0) { if (validSizes[i].MinSize == bitLength) { // assume MinSize = MaxSize return true; } } else { for (j = validSizes[i].MinSize; j<= validSizes[i].MaxSize; j += validSizes[i].SkipSize) { if (j == bitLength) { return true; } } } } return false; } static public SymmetricAlgorithm Create() { // use the crypto config system to return an instance of // the default SymmetricAlgorithm on this machine return Create("System.Security.Cryptography.SymmetricAlgorithm"); } static public SymmetricAlgorithm Create(String algName) { return (SymmetricAlgorithm) CryptoConfig.CreateFromName(algName); } public virtual ICryptoTransform CreateEncryptor() { return CreateEncryptor(Key, IV); } public abstract ICryptoTransform CreateEncryptor(byte[] rgbKey, byte[] rgbIV); public virtual ICryptoTransform CreateDecryptor() { return CreateDecryptor(Key, IV); } public abstract ICryptoTransform CreateDecryptor(byte[] rgbKey, byte[] rgbIV); public abstract void GenerateKey(); public abstract void GenerateIV(); } }
Link Menu

This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- FakeModelPropertyImpl.cs
- InternalMappingException.cs
- MembershipAdapter.cs
- EntityDataSourceDesigner.cs
- BuildProvider.cs
- TextElementEnumerator.cs
- StructuredProperty.cs
- XmlTextReaderImplHelpers.cs
- MethodImplAttribute.cs
- ApplicationFileParser.cs
- ActivityBindForm.cs
- ObjectStateEntryDbUpdatableDataRecord.cs
- XmlQualifiedNameTest.cs
- FixUp.cs
- _ProxyChain.cs
- HttpModule.cs
- DataColumnChangeEvent.cs
- Font.cs
- ItemCheckedEvent.cs
- QueryResults.cs
- TakeOrSkipQueryOperator.cs
- XpsFixedPageReaderWriter.cs
- BuildProvider.cs
- ToolStripDropDownItem.cs
- AnnotationHelper.cs
- ExtenderControl.cs
- SimpleTypesSurrogate.cs
- FrameworkElement.cs
- UserMapPath.cs
- DBPropSet.cs
- SqlDataSourceCache.cs
- SByte.cs
- ObjectView.cs
- JoinSymbol.cs
- IWorkflowDebuggerService.cs
- CatalogPartCollection.cs
- CatalogPart.cs
- CapabilitiesSection.cs
- SqlCacheDependency.cs
- AuthenticationService.cs
- HttpConfigurationContext.cs
- ComponentEvent.cs
- StreamWriter.cs
- CustomError.cs
- OSEnvironmentHelper.cs
- AssociationSet.cs
- Process.cs
- DrawingImage.cs
- FactoryGenerator.cs
- FileSystemInfo.cs
- DataGridPreparingCellForEditEventArgs.cs
- BamlRecordHelper.cs
- MatrixAnimationBase.cs
- QueryableFilterRepeater.cs
- ItemList.cs
- BindingContext.cs
- Sequence.cs
- HttpListenerContext.cs
- FormView.cs
- mediaclock.cs
- XPathBuilder.cs
- ValidatorUtils.cs
- PrintPreviewDialog.cs
- EventRoute.cs
- RowToFieldTransformer.cs
- InvokePattern.cs
- XmlSiteMapProvider.cs
- StorageModelBuildProvider.cs
- latinshape.cs
- WebPageTraceListener.cs
- NotifyParentPropertyAttribute.cs
- SessionStateModule.cs
- BuilderPropertyEntry.cs
- AssociativeAggregationOperator.cs
- EntityModelBuildProvider.cs
- DeclaredTypeElementCollection.cs
- SuppressMessageAttribute.cs
- RecipientInfo.cs
- SqlException.cs
- XmlSerializationGeneratedCode.cs
- DataObjectCopyingEventArgs.cs
- TypeElement.cs
- PatternMatcher.cs
- DbConvert.cs
- WebPartConnectionsConnectVerb.cs
- CookieProtection.cs
- ToolboxItem.cs
- DbConnectionInternal.cs
- ProfessionalColors.cs
- DataServiceQueryOfT.cs
- JavaScriptString.cs
- CrossSiteScriptingValidation.cs
- Int32KeyFrameCollection.cs
- StyleCollectionEditor.cs
- OutputCache.cs
- PerfCounters.cs
- DataListCommandEventArgs.cs
- ProbeDuplexAsyncResult.cs
- DesignerUtils.cs
- WebServiceMethodData.cs