C# DES 加密/解密类库

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

namespace HyeyClass.Common
{
#region DES Class

/// <summary>
/// ClassName: DES 加密类
/// DES加密、解密类库，字符串加密结果使用BASE64编码返回，支持文件的加密和解密
/// Time:2010-04-30
/// Auther:Hyey.wl
/// DES 的摘要说明。
/// </summary>
public sealed class DES
{
/// <summary>
/// myiv is  iv
/// </summary>
string myiv = "Hyey20100430";
/// <summary>
/// mykey is key
/// </summary>
string mykey = "HyeyWl30";

/// <summary>
/// DES加密偏移量
/// 必须是>=8位长的字符串
/// </summary>
public string IV
{
get{ return myiv;}
set{ myiv = value;}
}

/// <summary>
/// DES加密的私钥
/// 必须是8位长的字符串
/// </summary>
public string Key
{
get{ return mykey;}
set{ mykey = value;}
}

public  DES()
{
//
// TODO: 在此处添加构造函数逻辑
//
}

/// <summary>
/// 对字符串进行DES加密
/// Encrypts the specified sourcestring.
/// </summary>
/// <param name="sourcestring">The sourcestring.待加密的字符串</param>
/// <returns>加密后的BASE64编码的字符串</returns>
public string Encrypt(string sourceString)
{
byte[] btKey = Encoding.Default.GetBytes(mykey);
byte[] btIV = Encoding.Default.GetBytes(myiv);
DESCryptoServiceProvider des = new DESCryptoServiceProvider();
using (MemoryStream ms = new MemoryStream())
{
byte[] inData = Encoding.Default.GetBytes(sourceString);
try
{
using (CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(btKey, btIV), CryptoStreamMode.Write))
{
cs.Write(inData, 0, inData.Length);
cs.FlushFinalBlock();
}

return Convert.ToBase64String(ms.ToArray());
}
catch
{
throw;
}
}

}

/// <summary>
/// Decrypts the specified encrypted string.
/// 对DES加密后的字符串进行解密
/// </summary>
/// <param name="encryptedString">The encrypted string.待解密的字符串</param>
/// <returns>解密后的字符串</returns>
public string Decrypt(string encryptedString)
{
byte[] btKey = Encoding.Default.GetBytes(mykey);
byte[] btIV = Encoding.Default.GetBytes(myiv);
DESCryptoServiceProvider des = new DESCryptoServiceProvider();

using (MemoryStream ms = new MemoryStream())
{
byte[] inData = Convert.FromBase64String(encryptedString);
try
{
using (CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(btKey, btIV), CryptoStreamMode.Write))
{
cs.Write(inData, 0, inData.Length);
cs.FlushFinalBlock();
}

return Encoding.Default.GetString(ms.ToArray());
}
catch
{
throw;
}
}

}

/// <summary>
/// Encrypts the file.
/// 对文件内容进行DES加密
/// </summary>
/// <param name="sourceFile">The source file.待加密的文件绝对路径</param>
/// <param name="destFile">The dest file.加密后的文件保存的绝对路径</param>
public void EncryptFile(string sourceFile, string destFile)
{
if (!File.Exists(sourceFile)) throw new FileNotFoundException("指定的文件路径不存在！", sourceFile);

byte[] btKey = Encoding.Default.GetBytes(key);
byte[] btIV = Encoding.Default.GetBytes(iv);
DESCryptoServiceProvider des = new DESCryptoServiceProvider();
byte[] btFile = File.ReadAllBytes(sourceFile);

using (FileStream fs = new FileStream(destFile, FileMode.Create, FileAccess.Write))
{
try
{
using (CryptoStream cs = new CryptoStream(fs, des.CreateEncryptor(btKey, btIV), CryptoStreamMode.Write))
{
cs.Write(btFile, 0, btFile.Length);
cs.FlushFinalBlock();
}
}
catch
{
throw;
}
finally
{
fs.Close();
}
}

}

/// <summary>
/// Encrypts the file.
/// 对文件内容进行DES加密，加密后覆盖掉原来的文件
/// </summary>
/// <param name="sourceFile">The source file.待加密的文件的绝对路径</param>
public void EncryptFile(string sourceFile)
{
EncryptFile(sourceFile, sourceFile);
}

/// <summary>
/// Decrypts the file.
/// 对文件内容进行DES解密
/// </summary>
/// <param name="sourceFile">The source file.待解密的文件绝对路径</param>
/// <param name="destFile">The dest file.解密后的文件保存的绝对路径</param>
public void DecryptFile(string sourceFile, string destFile)
{
if (!File.Exists(sourceFile)) throw new FileNotFoundException("指定的文件路径不存在！", sourceFile);

byte[] btKey = Encoding.Default.GetBytes(key);
byte[] btIV = Encoding.Default.GetBytes(iv);
DESCryptoServiceProvider des = new DESCryptoServiceProvider();
byte[] btFile = File.ReadAllBytes(sourceFile);

using (FileStream fs = new FileStream(destFile, FileMode.Create, FileAccess.Write))
{
try
{
using (CryptoStream cs = new CryptoStream(fs, des.CreateDecryptor(btKey, btIV), CryptoStreamMode.Write))
{
cs.Write(btFile, 0, btFile.Length);
cs.FlushFinalBlock();
}
}
catch
{
throw;
}
finally
{
fs.Close();
}
}

}

/// <summary>
/// Decrypts the file.
/// 对文件内容进行DES解密，加密后覆盖掉原来的文件.
/// </summary>
/// <param name="sourceFile">The source file.待解密的文件的绝对路径.</param>
public void DecryptFile(string sourceFile)
{
DecryptFile(sourceFile, sourceFile);
}
}
#endregion
}