Code:
/ FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / Security / Cryptography / HMAC.cs / 2 / HMAC.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== // // HMAC.cs // // // For test vectors, see RFC2104, e.g. http://www.faqs.org/rfcs/rfc2104.html // namespace System.Security.Cryptography { [System.Runtime.InteropServices.ComVisible(true)] public abstract class HMAC : KeyedHashAlgorithm { // // protected members // // an HMAC uses a hash function where data is hashed by iterating a basic compression // function on blocks of data. BlockSizeValue is the byte size of such a block private int blockSizeValue = 64; protected int BlockSizeValue { get { return blockSizeValue; } set { blockSizeValue = value; } } internal string m_hashName; internal HashAlgorithm m_hash1; internal HashAlgorithm m_hash2; // // private members // // m_inner = PaddedKey ^ {0x36,...,0x36} // m_outer = PaddedKey ^ {0x5C,...,0x5C} private byte[] m_inner; private byte[] m_outer; private bool m_hashing = false; private void UpdateIOPadBuffers () { if (m_inner == null) m_inner = new byte[BlockSizeValue]; if (m_outer == null) m_outer = new byte[BlockSizeValue]; int i; for (i=0; i < BlockSizeValue; i++) { m_inner[i] = 0x36; m_outer[i] = 0x5C; } for (i=0; i < KeyValue.Length; i++) { m_inner[i] ^= KeyValue[i]; m_outer[i] ^= KeyValue[i]; } } internal void InitializeKey (byte[] key) { // When we change the key value, we'll need to update the initial values of the inner and outter // computation buffers. In the case of correct HMAC vs Whidbey HMAC, these buffers could get // generated to a different size than when we started. m_inner = null; m_outer = null; if (key.Length > BlockSizeValue) { KeyValue = m_hash1.ComputeHash(key); // No need to call Initialize, ComputeHash will do it for us } else { KeyValue = (byte[]) key.Clone(); } UpdateIOPadBuffers(); } // // public properties // public override byte[] Key { get { return (byte[]) KeyValue.Clone(); } set { if (m_hashing) throw new CryptographicException(Environment.GetResourceString("Cryptography_HashKeySet")); InitializeKey(value); } } public string HashName { get { return m_hashName; } set { if (m_hashing) throw new CryptographicException(Environment.GetResourceString("Cryptography_HashNameSet")); m_hashName = value; // create the hash algorithms m_hash1 = HashAlgorithm.Create(m_hashName); m_hash2 = HashAlgorithm.Create(m_hashName); } } // // public methods // new static public HMAC Create () { return Create("System.Security.Cryptography.HMAC"); } new static public HMAC Create (string algorithmName) { return (HMAC) CryptoConfig.CreateFromName(algorithmName); } public override void Initialize () { m_hash1.Initialize(); m_hash2.Initialize(); m_hashing = false; } protected override void HashCore (byte[] rgb, int ib, int cb) { if (m_hashing == false) { m_hash1.TransformBlock(m_inner, 0, m_inner.Length, m_inner, 0); m_hashing = true; } m_hash1.TransformBlock(rgb, ib, cb, rgb, ib); } protected override byte[] HashFinal () { if (m_hashing == false) { m_hash1.TransformBlock(m_inner, 0, m_inner.Length, m_inner, 0); m_hashing = true; } // finalize the original hash m_hash1.TransformFinalBlock(new byte[0], 0, 0); byte[] hashValue1 = m_hash1.HashValue; // write the outer array m_hash2.TransformBlock(m_outer, 0, m_outer.Length, m_outer, 0); // write the inner hash and finalize the hash m_hash2.TransformBlock(hashValue1, 0, hashValue1.Length, hashValue1, 0); m_hashing = false; m_hash2.TransformFinalBlock(new byte[0], 0, 0); return m_hash2.HashValue; } // // IDisposable methods // protected override void Dispose (bool disposing) { if (disposing) { if (m_hash1 != null) m_hash1.Clear(); if (m_hash2 != null) m_hash2.Clear(); if (m_inner != null) Array.Clear(m_inner, 0, m_inner.Length); if (m_outer != null) Array.Clear(m_outer, 0, m_outer.Length); } // call the base class's Dispose base.Dispose(disposing); } } }
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- OleDbCommand.cs
- DataGridRelationshipRow.cs
- SystemFonts.cs
- RangeBase.cs
- _OSSOCK.cs
- TableLayout.cs
- DataGridLinkButton.cs
- MethodExpression.cs
- ThemeableAttribute.cs
- OracleParameterBinding.cs
- DurableInstanceContextProvider.cs
- MetadataHelper.cs
- TraceContextRecord.cs
- XamlStream.cs
- ReferencedType.cs
- BinHexEncoder.cs
- PersonalizablePropertyEntry.cs
- WebPartTransformerAttribute.cs
- DetailsViewUpdatedEventArgs.cs
- sqlpipe.cs
- AsyncDataRequest.cs
- ConstraintEnumerator.cs
- ComboBoxRenderer.cs
- DataGridAutoGeneratingColumnEventArgs.cs
- _DisconnectOverlappedAsyncResult.cs
- ListViewUpdatedEventArgs.cs
- SpoolingTaskBase.cs
- RangeExpression.cs
- DisableDpiAwarenessAttribute.cs
- XmlAttributeCollection.cs
- UnsafeNativeMethodsMilCoreApi.cs
- CompilerHelpers.cs
- DataGridState.cs
- XmlNamespaceManager.cs
- Errors.cs
- SchemaMapping.cs
- VirtualPath.cs
- GridViewColumnHeader.cs
- WebPartHeaderCloseVerb.cs
- ExternalFile.cs
- DBCSCodePageEncoding.cs
- ParserStreamGeometryContext.cs
- MSAANativeProvider.cs
- SafeFindHandle.cs
- ClientCultureInfo.cs
- TextEvent.cs
- TextParagraphProperties.cs
- DashStyle.cs
- ExpressionLink.cs
- DeclaredTypeValidatorAttribute.cs
- AuthenticationSection.cs
- RequestStatusBarUpdateEventArgs.cs
- Underline.cs
- mongolianshape.cs
- FacetDescriptionElement.cs
- DataControlFieldHeaderCell.cs
- RubberbandSelector.cs
- CodeStatement.cs
- ReflectionHelper.cs
- ExceptionCollection.cs
- MultiTouchSystemGestureLogic.cs
- ServiceNameElement.cs
- KnownTypesHelper.cs
- GorillaCodec.cs
- PathSegmentCollection.cs
- DeclarativeCatalogPart.cs
- Activator.cs
- BuildProvidersCompiler.cs
- ProfessionalColors.cs
- RowToParametersTransformer.cs
- XsdValidatingReader.cs
- ExpanderAutomationPeer.cs
- SubtreeProcessor.cs
- ClickablePoint.cs
- Stroke.cs
- TextEditorSelection.cs
- AdPostCacheSubstitution.cs
- StreamReader.cs
- PointLightBase.cs
- ToolStripRendererSwitcher.cs
- baseshape.cs
- StoryFragments.cs
- HtmlControlPersistable.cs
- ConnectionProviderAttribute.cs
- ColorPalette.cs
- OutputCacheModule.cs
- TreeViewDataItemAutomationPeer.cs
- NetworkInformationPermission.cs
- SqlCacheDependencyDatabase.cs
- HybridDictionary.cs
- RegexCharClass.cs
- TaiwanLunisolarCalendar.cs
- RegexCompilationInfo.cs
- SharedDp.cs
- Model3DGroup.cs
- NotifyParentPropertyAttribute.cs
- linebase.cs
- OleDbStruct.cs
- MsmqIntegrationBinding.cs
- XmlMembersMapping.cs