Code:
/ DotNET / DotNET / 8.0 / 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
- CompilerGeneratedAttribute.cs
- RightsManagementEncryptionTransform.cs
- Single.cs
- DataControlButton.cs
- FieldMetadata.cs
- LinkArea.cs
- RadioButtonBaseAdapter.cs
- CallbackWrapper.cs
- HtmlWindowCollection.cs
- ServicePoint.cs
- ToolStripSplitButton.cs
- AudioException.cs
- NetworkAddressChange.cs
- WebScriptEnablingBehavior.cs
- dbenumerator.cs
- TypeValidationEventArgs.cs
- TargetParameterCountException.cs
- EntityDataSourceDesigner.cs
- AppSettingsReader.cs
- CorePropertiesFilter.cs
- PasswordValidationException.cs
- ExcCanonicalXml.cs
- PromptBuilder.cs
- SchemaImporter.cs
- ObjectHandle.cs
- ScriptingJsonSerializationSection.cs
- ResourcesChangeInfo.cs
- RotateTransform.cs
- LambdaCompiler.Generated.cs
- XmlUrlEditor.cs
- DrawItemEvent.cs
- PositiveTimeSpanValidator.cs
- SQLResource.cs
- DecimalSumAggregationOperator.cs
- FilterUserControlBase.cs
- ISessionStateStore.cs
- XdrBuilder.cs
- CountdownEvent.cs
- IsolatedStorage.cs
- CodeIterationStatement.cs
- InitializerFacet.cs
- ConstraintEnumerator.cs
- ReadWriteSpinLock.cs
- MissingManifestResourceException.cs
- WebResponse.cs
- XmlCharCheckingReader.cs
- XmlEntityReference.cs
- XmlTypeAttribute.cs
- AccessDataSourceView.cs
- TypeGeneratedEventArgs.cs
- InterleavedZipPartStream.cs
- BuildProvidersCompiler.cs
- WindowsFormsSynchronizationContext.cs
- ScopedKnownTypes.cs
- ResourceReader.cs
- HostProtectionPermission.cs
- DataContractSerializerElement.cs
- OleDbDataAdapter.cs
- Label.cs
- DeflateInput.cs
- RequestCachePolicy.cs
- DataGridViewRowPrePaintEventArgs.cs
- CodeTypeParameterCollection.cs
- Rect3D.cs
- XmlDataLoader.cs
- TransformConverter.cs
- FixedDocumentSequencePaginator.cs
- PolygonHotSpot.cs
- StaticResourceExtension.cs
- ExceptionUtil.cs
- LinkTarget.cs
- FileEnumerator.cs
- LockedAssemblyCache.cs
- DataGrid.cs
- ContextMenuStripActionList.cs
- SelectionRange.cs
- XmlSchemaInclude.cs
- GCHandleCookieTable.cs
- IApplicationTrustManager.cs
- ISO2022Encoding.cs
- QueryCursorEventArgs.cs
- FormatException.cs
- OledbConnectionStringbuilder.cs
- PagerSettings.cs
- OdbcHandle.cs
- ProfilePropertyMetadata.cs
- PeerInvitationResponse.cs
- DecimalFormatter.cs
- CalendarDesigner.cs
- NameValueConfigurationElement.cs
- ListViewHitTestInfo.cs
- EventHandlersDesigner.cs
- Tile.cs
- HttpPostClientProtocol.cs
- UpdatePanel.cs
- PropertyMapper.cs
- TreeWalker.cs
- JpegBitmapEncoder.cs
- LineServicesCallbacks.cs
- TreeNode.cs