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/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Core / System / Security / Cryptography / CapiHashAlgorithm.cs / 1305376 / CapiHashAlgorithm.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== using System; using System.Diagnostics; using System.Diagnostics.CodeAnalysis; using System.Runtime.InteropServices; using System.Diagnostics.Contracts; using Microsoft.Win32.SafeHandles; namespace System.Security.Cryptography { ////// Implementation of a generic CAPI hashing algorithm, concrete HashAlgorithm classes /// implemented by CAPI can contain an instance of this class and delegate the work to it /// internal sealed class CapiHashAlgorithm : IDisposable { private CapiNative.AlgorithmId m_algorithmId; private SafeCspHandle m_cspHandle; private SafeCapiHashHandle m_hashHandle; //// [System.Security.SecurityCritical] public CapiHashAlgorithm(string provider, CapiNative.ProviderType providerType, CapiNative.AlgorithmId algorithm) { Contract.Requires(!String.IsNullOrEmpty(provider)); Contract.Requires((CapiNative.AlgorithmClass)((uint)algorithm & (uint)CapiNative.AlgorithmClass.Hash) == CapiNative.AlgorithmClass.Hash); Contract.Ensures(m_cspHandle != null && !m_cspHandle.IsInvalid && !m_cspHandle.IsClosed); Contract.Ensures(m_hashHandle != null && !m_hashHandle.IsInvalid && !m_hashHandle.IsClosed); m_algorithmId = algorithm; m_cspHandle = CapiNative.AcquireCsp(null, provider, providerType, CapiNative.CryptAcquireContextFlags.VerifyContext, true); Initialize(); } //// // // // // // // [System.Security.SecurityCritical] public void Dispose() { Contract.Ensures(m_hashHandle == null || m_hashHandle.IsClosed); Contract.Ensures(m_cspHandle == null || m_cspHandle.IsClosed); if (m_hashHandle != null) { m_hashHandle.Dispose(); } if (m_cspHandle != null) { m_cspHandle.Dispose(); } } ///// // // // /// Reset the hash algorithm to begin hashing a new set of data /// //// [System.Security.SecurityCritical] [SuppressMessage("Microsoft.Security", "CA2122:DoNotIndirectlyExposeMethodsWithLinkDemands", Justification = "Reviewed")] public void Initialize() { Contract.Ensures(m_hashHandle != null && !m_hashHandle.IsInvalid && !m_hashHandle.IsClosed); Contract.Assert(m_cspHandle != null); // Try to create a new hash algorithm to use SafeCapiHashHandle newHashAlgorithm = null; if (!CapiNative.UnsafeNativeMethods.CryptCreateHash(m_cspHandle, m_algorithmId, SafeCapiKeyHandle.InvalidHandle, 0, out newHashAlgorithm)) { // BadAlgorithmId means that this CSP does not support the specified algorithm, which means // that we're on a platform that does not support the given hash function. int error = Marshal.GetLastWin32Error(); if (error == (int)CapiNative.ErrorCode.BadAlgorithmId) { throw new PlatformNotSupportedException(SR.GetString(SR.Cryptography_PlatformNotSupported)); } else { throw new CryptographicException(error); } } // If we created a new algorithm, dispose of the old one and use the new one Debug.Assert(newHashAlgorithm != null, "newHashAlgorithm != null"); if (m_hashHandle != null) { m_hashHandle.Dispose(); } m_hashHandle = newHashAlgorithm; } ///// // // // // // // // // /// Hash a block of data /// //// [System.Security.SecurityCritical] public void HashCore(byte[] array, int ibStart, int cbSize) { Contract.Assert(m_hashHandle != null); if (array == null) { throw new ArgumentNullException("array"); } if (ibStart < 0 || ibStart > array.Length - cbSize) { throw new ArgumentOutOfRangeException("ibStart"); } if (cbSize < 0 || cbSize > array.Length) { throw new ArgumentOutOfRangeException("cbSize"); } byte[] hashData = new byte[cbSize]; Buffer.BlockCopy(array, ibStart, hashData, 0, cbSize); if (!CapiNative.UnsafeNativeMethods.CryptHashData(m_hashHandle, hashData, cbSize, 0)) { throw new CryptographicException(Marshal.GetLastWin32Error()); } } ///// // // /// Complete the hash, returning its value /// //// [System.Security.SecurityCritical] public byte[] HashFinal() { Contract.Ensures(Contract.Result// // () != null); Contract.Assert(m_hashHandle != null); return CapiNative.GetHashParameter(m_hashHandle, CapiNative.HashParameter.HashValue); } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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