C#做的一个加密/解密的类

代码如下：

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

namespace SEDO
{ 
 
 // 定义加密类型的枚举
 public enum EncryptionAlgorithm {Des = 1, Rc2, Rijndael, TripleDes};

 // 定义加密类
 internal class EncryptTransformer
 {
  private EncryptionAlgorithm algorithmID;
  private byte[] initVec;
  private byte[] encKey;

  internal EncryptTransformer(EncryptionAlgorithm algId)
  {
   //Save the algorithm being used.
   algorithmID = algId;
  }

  internal ICryptoTransform GetCryptoServiceProvider(byte[] bytesKey)
  {
   // 当数据密钥 Key 或者初始化向量 IV 为空的时候，将使用加密对象自动产生的密钥 Key 或者初始化向量 IV
   switch (algorithmID)
   {
    case EncryptionAlgorithm.Des:
    {
     DES des = new DESCryptoServiceProvider();
     des.Mode = CipherMode.CBC;

     // See if a key was provided
     if (null == bytesKey)
     {
      encKey = des.Key;
     }
     else
     {
      des.Key = bytesKey;
      encKey = des.Key;
     }
     // See if the client provided an initialization vector
     if (null == initVec)
     { // Have the algorithm create one
      initVec = des.IV;
     }
     else
     { //No, give it to the algorithm
      des.IV = initVec;
     }
     return des.CreateEncryptor();
    }
    case EncryptionAlgorithm.TripleDes:
    {
     TripleDES des3 = new TripleDESCryptoServiceProvider();
     des3.Mode = CipherMode.CBC;
     // See if a key was provided
     if (null == bytesKey)
     {
      encKey = des3.Key;
     }
     else
     {
      des3.Key = bytesKey;
      encKey = des3.Key;
     }
     // See if the client provided an IV
     if (null == initVec)
     { //Yes, have the alg create one
      initVec = des3.IV;
     }
     else
     { //No, give it to the alg.
      des3.IV = initVec;
     }
     return des3.CreateEncryptor();
    }
    case EncryptionAlgorithm.Rc2:
    {
     RC2 rc2 = new RC2CryptoServiceProvider();
     rc2.Mode = CipherMode.CBC;
     // Test to see if a key was provided
     if (null == bytesKey)
     {
      encKey = rc2.Key;
     }
     else
     {
      rc2.Key = bytesKey;
      encKey = rc2.Key;
     }
     // See if the client provided an IV

if (null == initVec)
     { //Yes, have the alg create one
      initVec = rc2.IV;
     }
     else
     { //No, give it to the alg.
      rc2.IV = initVec;
     }
     return rc2.CreateEncryptor();
    }
    case EncryptionAlgorithm.Rijndael:
    {
     Rijndael rijndael = new RijndaelManaged();
     rijndael.Mode = CipherMode.CBC;
     // Test to see if a key was provided
     if(null == bytesKey)
     {
      encKey = rijndael.Key;
     }
     else
     {
      rijndael.Key = bytesKey;
      encKey = rijndael.Key;
     }
     // See if the client provided an IV
     if(null == initVec)
     { //Yes, have the alg create one
      initVec = rijndael.IV;
     }
     else
     { //No, give it to the alg.
      rijndael.IV = initVec;
     }
     return rijndael.CreateEncryptor();
    }
    default:
    {
     throw new CryptographicException("Algorithm ID '" +
      algorithmID +
      "' not supported.");
    }
   }
  }

  // 加密的偏移向量
  internal byte[] IV
  {
   get{return initVec;}
   set{initVec = value;}
  }
  // 加密的密钥
  internal byte[] Key
  {
   get{return encKey;}
   set{encKey = value;}
  }

 }

 // 定义解密类
 internal class DecryptTransformer
 {
  private EncryptionAlgorithm algorithmID;
  private byte[] initVec;
  private byte[] encKey;

  internal DecryptTransformer(EncryptionAlgorithm deCryptId)
  {
   algorithmID = deCryptId;
  }

  // 加密的偏移向量
  internal byte[] IV
  {
   get{return initVec;}
   set{initVec = value;}
  }
  
  // 加密的密钥
  internal byte[] Key
  {
   get{return encKey;}
   set{encKey = value;}
  }

  internal ICryptoTransform GetCryptoServiceProvider(byte[] bytesKey)
  {
   // 当数据密钥 Key 或者初始化向量 IV 为空的时候，将使用加密对象自动产生的密钥 Key 或者初始化向量 IV
   switch (algorithmID)
   {
    case EncryptionAlgorithm.Des:
    {
     DES des = new DESCryptoServiceProvider();
     des.Mode = CipherMode.CBC;
     des.Key = bytesKey;
     des.IV = initVec;
     return des.CreateDecryptor();
    }
    case EncryptionAlgorithm.TripleDes:
    {
     TripleDES des3 = new TripleDESCryptoServiceProvider();
     des3.Mode = CipherMode.CBC;
     return des3.CreateDecryptor(bytesKey, initVec);
    }
    case EncryptionAlgorithm.Rc2:
    {
     RC2 rc2 = new RC2CryptoServiceProvider();
     rc2.Mode = CipherMode.CBC;
     return rc2.CreateDecryptor(bytesKey, initVec);
    }
    case EncryptionAlgorithm.Rijndael:
    {
     Rijndael rijndael = new RijndaelManaged();
     rijndael.Mode = CipherMode.CBC;
     return rijndael.CreateDecryptor(bytesKey, initVec);
    }
    default:
    {
     throw new CryptographicException("Algorithm ID '" +
      algorithmID +
      "' not supported.");
    }
   }
  } //end GetCryptoServiceProvider
 
 }

 // 定义加密者类
 public class Encryptor
 {
  private EncryptTransformer transformer;
  private byte[] initVec;
  private byte[] encKey;
 
  public Encryptor(EncryptionAlgorithm algId)
  {
   transformer = new EncryptTransformer(algId);
  }

  public byte[] Encrypt(byte[] bytesData, byte[] bytesKey,byte[] bytesIV)
  {
   // 设置流对象用来保存加密数据字节流 .
   MemoryStream memStreamEncryptedData = new MemoryStream();
   
   transformer.IV=bytesIV;
   transformer.Key=bytesKey;
 
   ICryptoTransform transform = transformer.GetCryptoServiceProvider(bytesKey);
   CryptoStream encStream = new CryptoStream(memStreamEncryptedData,transform,CryptoStreamMode.Write);

   try
   {
    // 将加密数据写进流对象
    encStream.Write(bytesData, 0, bytesData.Length);
   }
   catch(Exception ex)
   {

throw new Exception(" 在数据加密的时候出现错误！错误提示： \n"  + ex.Message);
   }
   
   // 设置加密的 Key 和初始向量 IV 属性
   encKey = transformer.Key;
   initVec = transformer.IV;

   encStream.FlushFinalBlock();
   encStream.Close();

   //Send the data back.
   return memStreamEncryptedData.ToArray();
  }

  public byte[] IV
  {
   get{return initVec;}
   set{initVec = value;}
  }

  public byte[] Key
  {
   get{return encKey;}
   set{encKey = value;}
  }
 
 }

 // 定义解密者类
 public class Decryptor
 {
  private DecryptTransformer transformer;
  private byte[] initVec;
  private byte[] encKey;

  public Decryptor(EncryptionAlgorithm algId)
  {
   transformer = new DecryptTransformer(algId);
  }

  public byte[] Decrypt(byte[] bytesData, byte[] bytesKey,byte[] bytesIV)
  {
   // 设置流对象用来保存解密数据字节流 .
   MemoryStream memStreamDecryptedData = new MemoryStream();

   //Pass in the initialization vector.
   transformer.IV = bytesIV;
   transformer.Key = bytesKey;

   ICryptoTransform transform = transformer.GetCryptoServiceProvider(bytesKey);
   CryptoStream decStream = new CryptoStream(memStreamDecryptedData,transform, CryptoStreamMode.Write);
   
   try
   {
    decStream.Write(bytesData, 0, bytesData.Length);
   }
   catch(Exception ex)
   {
    throw new Exception(" 在数据解密的时候出现错误！错误提示： \n" + ex.Message);
   }
   decStream.FlushFinalBlock();
   decStream.Close();
   // 返回解密数据 .
   return memStreamDecryptedData.ToArray();
  }

  public byte[] IV
  {
   get{return initVec;}
   set{initVec = value;}
  }

  public byte[] Key
  {
   get{return encKey;}
   set{encKey = value;}
  }
 
 }

 // 类描述：文件加密 / 解密类
 public class SecurityFile
 {
  private DecryptTransformer Dec_Transformer;    // 解密转换器
  private EncryptTransformer Enc_Transformer;    // 加密转换器
  private byte[] initVec;
  private byte[] encKey;

  public SecurityFile(EncryptionAlgorithm algId)
  {
   Dec_Transformer = new DecryptTransformer(algId);
   Enc_Transformer = new EncryptTransformer(algId);
  }

  // 加密的偏移向量
  internal byte[] IV
  {
   get{return initVec;}
   set{initVec = value;}
  }
  // 加密的密钥
  internal byte[] Key
  {
   get{return encKey;}
   set{encKey = value;}
  }

  // 功能描述：加密文件
  public void EncryptFile(string inFileName, string outFileName, byte[] bytesKey, byte[] bytesIV)
  {
   try
   {
    FileStream fin = new FileStream(inFileName, FileMode.Open, FileAccess.Read);
    FileStream fout = new FileStream(outFileName, FileMode.OpenOrCreate, FileAccess.Write);
    fout.SetLength(0);
      
    //Create variables to help with read and write.
    byte[] bin = new byte[100]; //This is intermediate storage for the encryption.
    long rdlen = 0;              //This is the total number of bytes written.
    long totlen = fin.Length;    //This is the total length of the input file.
    int len;                     //This is the number of bytes to be written at a time.
 
    Enc_Transformer.IV=bytesIV;
    Enc_Transformer.Key=bytesKey;

    ICryptoTransform transform = Enc_Transformer.GetCryptoServiceProvider(bytesKey);         
    CryptoStream encStream = new CryptoStream(fout, transform, CryptoStreamMode.Write);
                             
    //Read from the input file, then encrypt and write to the output file.
    while(rdlen < totlen)
    {
     len = fin.Read(bin, 0, 100);
     encStream.Write(bin, 0, len);
     rdlen = rdlen + len;     
    }
 
    encStream.Close(); 
    fout.Close();
    fin.Close();    
   }
   catch(Exception ex)
   {
    throw new Exception(" 在文件加密的时候出现错误！错误提示： \n" + ex.Message);
   }
  }

  // 功能描述：解密文件
  public void DecryptFile(string inFileName, string outFileName, byte[] bytesKey, byte[] bytesIV)
  {
   try
   {
    FileStream fin = new FileStream(inFileName, FileMode.Open, FileAccess.Read);

FileStream fout = new FileStream(outFileName, FileMode.OpenOrCreate, FileAccess.Write);
    fout.SetLength(0);
      
    //Create variables to help with read and write.
    byte[] bin = new byte[100]; //This is intermediate storage for the encryption.
    long rdlen = 0;              //This is the total number of bytes written.
    long totlen = fin.Length;    //This is the total length of the input file.
    int len;                     //This is the number of bytes to be written at a time.
 
    Dec_Transformer.IV=bytesIV;
    Dec_Transformer.Key=bytesKey;

    ICryptoTransform transform = Dec_Transformer.GetCryptoServiceProvider(bytesKey);         
    CryptoStream encStream = new CryptoStream(fout, transform, CryptoStreamMode.Write);
                             
    //Read from the input file, then encrypt and write to the output file.
    while(rdlen < totlen)
    {
     len = fin.Read(bin, 0, 100);
     encStream.Write(bin, 0, len);
     rdlen = rdlen + len;     
    }
 
    encStream.Close(); 
    fout.Close();
    fin.Close();    
   }
   catch(Exception ex)
   {
    throw new Exception(" 在文件加密的时候出现错误！错误提示： \n" + ex.Message);
   }
  }
 
 }

}