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
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- XmlDsigSep2000.cs
- TcpTransportBindingElement.cs
- Selector.cs
- ExpressionCopier.cs
- ToolStripSystemRenderer.cs
- unsafenativemethodsother.cs
- PassportAuthentication.cs
- NativeMethods.cs
- DataPagerFieldCommandEventArgs.cs
- ApplicationInfo.cs
- DummyDataSource.cs
- LinqDataSource.cs
- CopyAction.cs
- IntranetCredentialPolicy.cs
- TextAction.cs
- TextTreePropertyUndoUnit.cs
- AssociatedControlConverter.cs
- ResourceDictionary.cs
- ProfileInfo.cs
- SystemIcmpV4Statistics.cs
- KeySpline.cs
- SqlError.cs
- EventMappingSettings.cs
- Message.cs
- ProgressBar.cs
- ServiceMemoryGates.cs
- UnknownWrapper.cs
- MappingMetadataHelper.cs
- DataPagerFieldItem.cs
- PartialCachingAttribute.cs
- UpdateTranslator.cs
- CacheAxisQuery.cs
- SettingsProperty.cs
- GeneralTransformGroup.cs
- DataRowCollection.cs
- StreamReader.cs
- XmlComment.cs
- ReflectionUtil.cs
- ValueUtilsSmi.cs
- LogPolicy.cs
- WriteTimeStream.cs
- QilScopedVisitor.cs
- ObjectTag.cs
- InputLangChangeEvent.cs
- InputMethod.cs
- IndexedString.cs
- DispatcherHooks.cs
- Delay.cs
- MenuItemStyleCollection.cs
- TextProperties.cs
- WebPartZoneCollection.cs
- URLMembershipCondition.cs
- Util.cs
- Animatable.cs
- DtrList.cs
- TCEAdapterGenerator.cs
- IncomingWebResponseContext.cs
- SqlFacetAttribute.cs
- StorageScalarPropertyMapping.cs
- SqlDataSourceFilteringEventArgs.cs
- PageParser.cs
- PackageDigitalSignatureManager.cs
- PenLineCapValidation.cs
- Brushes.cs
- ArgIterator.cs
- TreeNode.cs
- FtpWebResponse.cs
- RegexStringValidatorAttribute.cs
- TraceInternal.cs
- MLangCodePageEncoding.cs
- _NegotiateClient.cs
- ScrollChrome.cs
- DefaultAsyncDataDispatcher.cs
- ToolStripItemBehavior.cs
- DesignerLoader.cs
- SchemaInfo.cs
- ValidationPropertyAttribute.cs
- BinaryVersion.cs
- lengthconverter.cs
- infer.cs
- InvalidEnumArgumentException.cs
- SimpleType.cs
- XmlSchemaImport.cs
- ACL.cs
- BeginEvent.cs
- ConnectionManagementElement.cs
- XmlIlVisitor.cs
- FilterEventArgs.cs
- ServicePointManagerElement.cs
- XmlSignatureProperties.cs
- StyleHelper.cs
- TypedReference.cs
- TextHidden.cs
- SessionIDManager.cs
- IPGlobalProperties.cs
- WebPartTransformerCollection.cs
- XmlElement.cs
- ValidationSummary.cs
- Formatter.cs
- Relationship.cs