字符和文件加密类，128位加密

using System;using System.Security;using System.Security.Cryptography;using System.IO;using System.Text;

namespace MySecurity{public class MySecurity {  public MySecurity()  {   //   // TODO: 在此处添加构造函数逻辑   //  }  private string key="1234567890"; //默认密钥

  private byte[] sKey;  private byte[] sIV;

  /// <summary>  /// 加密字符串  /// </summary>  /// <param name="inputStr">输入字符串</param>  /// <param name="keyStr">密码，可以为“”</param>  /// <returns>输出加密后字符串</returns>  static public string SEncryptString(string inputStr,string keyStr)  {       MySecurity ws=new MySecurity();       return ws.EncryptString(inputStr,keyStr);  }

  /// <summary>  /// 加密字符串  /// </summary>  /// <param name="inputStr">输入字符串</param>  /// <param name="keyStr">密码，可以为“”</param>  /// <returns>输出加密后字符串</returns>  public string EncryptString(string inputStr,string keyStr)  {       DESCryptoServiceProvider des = new DESCryptoServiceProvider();        if(keyStr=="")            keyStr=key;       byte[] inputByteArray = Encoding.Default.GetBytes(inputStr);       byte[] keyByteArray=Encoding.Default.GetBytes(keyStr);       SHA1 ha=new SHA1Managed();       byte[] hb=ha.ComputeHash(keyByteArray);       sKey=new byte[8];       sIV=new byte[8];       for(int i=0;i<8;i++)            sKey[i]=hb[i];       for(int i=8;i<16;i++)            sIV[i-8]=hb[i];       des.Key=sKey;       des.IV=sIV;       MemoryStream ms = new MemoryStream();       CryptoStream cs = new CryptoStream(ms,des.CreateEncryptor(),CryptoStreamMode.Write);         cs.Write(inputByteArray, 0, inputByteArray.Length);         cs.FlushFinalBlock();         StringBuilder ret = new  StringBuilder();         foreach(byte b in ms.ToArray())         {              ret.AppendFormat("{0:X2}", b);         }         cs.Close();       ms.Close();       return  ret.ToString();    }

  /// <summary>  /// 加密文件  /// </summary>  /// <param name="filePath">输入文件路径</param> /// <param name="savePath">加密后输出文件路径</param>  /// <param name="keyStr">密码，可以为“”</param>  /// <returns></returns>  public bool EncryptFile(string filePath,string savePath,string keyStr)  {       DESCryptoServiceProvider des = new DESCryptoServiceProvider();        if(keyStr=="")            keyStr=key;       FileStream fs=File.OpenRead(filePath);       byte[] inputByteArray =new byte[fs.Length];        fs.Read(inputByteArray,0,(int)fs.Length);       fs.Close();       byte[] keyByteArray=Encoding.Default.GetBytes(keyStr);       SHA1 ha=new SHA1Managed();       byte[] hb=ha.ComputeHash(keyByteArray);       sKey=new byte[8];       sIV=new byte[8];       for(int i=0;i<8;i++)            sKey[i]=hb[i];       for(int i=8;i<16;i++)            sIV[i-8]=hb[i];       des.Key=sKey;       des.IV=sIV;       MemoryStream ms = new MemoryStream();       CryptoStream cs = new CryptoStream(ms,des.CreateEncryptor(),CryptoStreamMode.Write);         cs.Write(inputByteArray, 0, inputByteArray.Length);         cs.FlushFinalBlock();       fs=File.OpenWrite(savePath);       foreach(byte b in ms.ToArray())         {              fs.WriteByte(b);         }        fs.Close();       cs.Close();       ms.Close();       return true;  }

  /// <summary>  /// 解密字符串  /// </summary>  /// <param name="inputStr">要解密的字符串</param>  /// <param name="keyStr">密钥</param>  /// <returns>解密后的结果</returns>  public string DecryptString(string inputStr,string keyStr)  {       DESCryptoServiceProvider des = new DESCryptoServiceProvider();        if(keyStr=="")            keyStr=key;       byte[] inputByteArray = new byte[inputStr.Length / 2];         for(int x = 0; x < inputStr.Length / 2; x++)         {              int i = (Convert.ToInt32(inputStr.Substring(x * 2, 2), 16));              inputByteArray[x]  =  (byte)i;         }         byte[] keyByteArray=Encoding.Default.GetBytes(keyStr);       SHA1 ha=new SHA1Managed();       byte[] hb=ha.ComputeHash(keyByteArray);       sKey=new byte[8];       sIV=new byte[8];       for(int i=0;i<8;i++)            sKey[i]=hb[i];       for(int i=8;i<16;i++)            sIV[i-8]=hb[i];       des.Key=sKey;       des.IV=sIV;       MemoryStream ms = new MemoryStream();       CryptoStream cs = new CryptoStream(ms,des.CreateDecryptor(),CryptoStreamMode.Write);         cs.Write(inputByteArray, 0, inputByteArray.Length);         cs.FlushFinalBlock();         StringBuilder ret = new StringBuilder();         return System.Text.Encoding.Default.GetString(ms.ToArray());    }

  /// <summary>  /// 解密文件  /// </summary>  /// <param name="filePath">输入文件路径</param> /// <param name="savePath">解密后输出文件路径</param>  /// <param name="keyStr">密码，可以为“”</param>  /// <returns></returns>    public bool DecryptFile(string filePath,string savePath,string keyStr)  {       DESCryptoServiceProvider des = new DESCryptoServiceProvider();        if(keyStr=="")            keyStr=key;       FileStream fs=File.OpenRead(filePath);       byte[] inputByteArray =new byte[fs.Length];        fs.Read(inputByteArray,0,(int)fs.Length);       fs.Close();       byte[] keyByteArray=Encoding.Default.GetBytes(keyStr);       SHA1 ha=new SHA1Managed();       byte[] hb=ha.ComputeHash(keyByteArray);       sKey=new byte[8];       sIV=new byte[8];       for(int i=0;i<8;i++)            sKey[i]=hb[i];       for(int i=8;i<16;i++)            sIV[i-8]=hb[i];       des.Key=sKey;       des.IV=sIV;       MemoryStream ms = new MemoryStream();       CryptoStream cs = new CryptoStream(ms,des.CreateDecryptor(),CryptoStreamMode.Write);         cs.Write(inputByteArray, 0, inputByteArray.Length);         cs.FlushFinalBlock();       fs=File.OpenWrite(savePath);       foreach(byte b in ms.ToArray())         {              fs.WriteByte(b);         }        fs.Close();       cs.Close();       ms.Close();       return true;  }

  /// <summary>  /// 解密字符串  /// </summary>  /// <param name="inputStr">要解密的字符串</param>  /// <param name="keyStr">密钥</param>  /// <returns>解密后的结果</returns>  static public string SDecryptString(string inputStr,string keyStr)  {       MySecurity ws=new MySecurity();       return ws.DecryptString(inputStr,keyStr);  } }}