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在.net Flamework完全版中对System.Security.Cryptography名字空间下的加密类支持得很好。但在精简版中却没有提供这个名字空间中的相应的类。在用.net写Pocket PC程序的时候用的加密算法的时候确实比较麻烦。一般有两种方式来解决这个问题。OpenNetCF（www.openetcf.org）提供了System.Security.Cryptography名字空间下的各个类的模仿,但它的提供缺乏灵活性：比如在对称加密的时候，用户无法设置Padding, CipherMode等属性。而且它的提供方法和完全版的.net下的类的接口不一致，这样给用户造成困惑。另一种方式就是自己动手对cryptoAPI进行自己封装。 最近出于工作需要对MD5CryptoServiceProvider进行了实现，这个类的接口和完整版下面的接口完全一致。 Implementation of the "System.Security.Cryptography.MD5CryptoServiceProvider" class. public sealed class MD5CryptoServiceProvider : MD5 { public MD5CryptoServiceProvider() { Initialize(); m_Disposed = false; } public override void Initialize() { if (m_Disposed) throw new ObjectDisposedException(this.GetType().FullName); if (m_Hash != IntPtr.Zero) { Crypto.CryptDestroyHash(m_Hash); } m_Prov = Crypto.AcquireContext(ProvType.RSA_FULL); bool retVal=Crypto.CryptCreateHash(m_Prov, (uint)CalgHash.MD5, IntPtr.Zero, 0, out m_Hash); } protected override void HashCore(byte[] array, int ibStart, int cbSize) { if (m_Disposed) throw new ObjectDisposedException(this.GetType().FullName); byte[] copy = (byte[]) array.Clone(); //Array.Copy(array, ibStart, copy, 0, cbSize); bool retVal=false; retVal=Crypto.CryptHashData(m_Hash, copy, copy.Length, 0); } protected override byte[] HashFinal() { if (m_Disposed) throw new ObjectDisposedException(this.GetType().FullName); byte [] data = new byte[0]; uint dataLen = 0; uint flags = 0; //size bool retVal = Crypto.CryptGetHashParam(m_Hash, (uint) HashParam.HASHVAL, data, ref dataLen, flags); if(234 == Marshal.GetLastWin32Error())//MORE_DATA = 234, { //data data = new byte[dataLen]; retVal = Crypto.CryptGetHashParam(m_Hash, (uint) HashParam.HASHVAL, data, ref dataLen, flags); } return data; } protected override void Dispose(bool disposing) { if (!m_Disposed) { if (m_Hash != IntPtr.Zero) { bool retVal=Crypto.CryptDestroyHash(m_Hash); m_Hash = IntPtr.Zero; } if(m_Prov!=IntPtr.Zero) { Crypto.CryptReleaseContext(m_Prov, 0); m_Prov=IntPtr.Zero; } try { GC.SuppressFinalize(this); } catch {} m_Disposed = true; } } ~MD5CryptoServiceProvider() { Clear(); } private IntPtr m_Hash=IntPtr.Zero; private bool m_Disposed; private IntPtr m_Prov=IntPtr.Zero; } public abstract class MD5 : HashAlgorithm { // Constructor. protected MD5() { HashSizeValue = 128; } // Create a new instance of the "MD5" class. public new static MD5 Create() { return (MD5)(CryptoConfig.CreateFromName (CryptoConfig.MD5Default, null)); } public new static MD5 Create(String algName) { return (MD5)(CryptoConfig.CreateFromName(algName, null)); } }; // class MD5 P/Invoke the cryotoAPI public class Crypto { [DllImport("coredll.dll", EntryPoint="CryptAcquireContext")] public static extern bool CryptAcquireContext(out IntPtr hProv, string pszContainer, string pszProvider, uint dwProvType, uint dwFlags); [DllImport("coredll.dll", EntryPoint="CryptCreateHash")] public static extern bool CryptCreateHash(IntPtr hProv, uint Algid, IntPtr hKey, uint dwFlags, out IntPtr phHash); [DllImport("coredll.dll", EntryPoint="CryptDestroyHash")] public static extern bool CryptDestroyHash(IntPtr hHash); [DllImport("coredll.dll", EntryPoint="CryptHashData")] public static extern bool CryptHashData(IntPtr hHash, byte[] pbData, int dwDataLen, uint dwFlags); [DllImport("coredll.dll", EntryPoint="CryptGetHashParam", SetLastError=true)] public static extern bool CryptGetHashParam(IntPtr hHash, uint dwParam, byte[] pbData, ref uint pdwDataLen, uint dwFlags); [DllImport("coredll.dll", EntryPoint="CryptReleaseContext")] public static extern bool CryptReleaseContext(IntPtr hProv, uint dwFlags); public static IntPtr AcquireContext() { return AcquireContext("MD5Container", ProvName.MS_ENHANCED_PROV, ProvType.RSA_FULL, ContextFlag.NONE); } public static IntPtr AcquireContext(string container) { return AcquireContext(container, ProvName.MS_ENHANCED_PROV, ProvType.RSA_FULL, ContextFlag.NONE); } public static IntPtr AcquireContext(ProvType provType) { return AcquireContext(null, null, provType, ContextFlag.NONE); } public static IntPtr AcquireContext(string provName, ProvType provType) { return AcquireContext(null, provName, provType, ContextFlag.NONE); } public static IntPtr AcquireContext(string provName, ProvType provType, ContextFlag conFlag) { return AcquireContext(null, provName, provType, conFlag); } public static IntPtr AcquireContext(string conName, string provName, ProvType provType) { return AcquireContext(conName, provName, provType, ContextFlag.NONE); } public static IntPtr AcquireContext(string conName, string provName, ProvType provType, ContextFlag conFlag) { IntPtr hProv; bool retVal = Crypto.CryptAcquireContext(out hProv, conName, provName, (uint) provType, (uint) conFlag); if(!retVal) //try creating a new key container { retVal = Crypto.CryptAcquireContext(out hProv, conName, provName, (uint) provType, (uint) ContextFlag.NEWKEYSET); } if(hProv == IntPtr.Zero) throw new Exception("System.Security.Cryptography"); return hProv; } } 代码下载在codeproject上有：http://www.codeproject.com/useritems/MD5CryptoServiceProvider.asp Reference: Dot NET Compact Framework Kick Start 2003 www.opennetcf.org http://www.koders.com/csharp/fidC21861B5F1B717EC1FDEC006DBD0B8226B92D878.aspx 返回类别: 教程 上一教程: Websharp使用说明（4） 下一教程: C#异步数据接收串口操作类 您可以阅读与".net Compact Flamework中MD5CryptoServiceProvider的实现"相关的教程: · ASP.NET下MVC设计模式的实现 · ASP.NET中树形图的实现 · .NET Framework 中多语言支持的实现 · NET环境下有关打印页面设置、打印机设置、打印预览对话框的实现（二） · .NET Compact Framework的强盛二维图形引擎 |
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