C#编写的Base64加密和解密类

这个C#类是一个基于Base64的加密和解密类，用户可以可以使用默认的秘钥进行加密、解密，也可以自己设定秘钥进行加密和解密，非常实用

代码一：非常精简的代码

/// <summary>
/// Base64加密，解密方法
/// </summary>
/// <paramname="s">输入字符串</param>
/// <paramname="c">true-加密,false-解密</param>
static public string base64(string s, bool c)
{
  if (c)
  {
    returnSystem.Convert.ToBase64String(System.Text.Encoding.Default.GetBytes(s));
  }
  else
  {
    try
{
  returnSystem.Text.Encoding.Default.GetString(System.Convert.FromBase64String(pwdString));
}
catch(Exception exp)
{
  returnexp.Message;
}
  }
}

代码二：

using System;
using System.Security.Cryptography;
using System.Text;
namespace DotNet.Utilities
{
  /// <summary>
  /// Encrypt 的摘要说明。
  /// </summary>
  public class DEncrypt
  {
    /// <summary>
    /// 构造方法
    /// </summary>
    public DEncrypt()
    {
    }

    #region 使用 缺省密钥字符串 加密/解密string

    /// <summary>
    /// 使用缺省密钥字符串加密string
    /// </summary>
    /// <param name="original">明文</param>
    /// <returns>密文</returns>
    public static string Encrypt(string original)
    {
      return Encrypt(original,"sharejs.com");
    }
    /// <summary>
    /// 使用缺省密钥字符串解密string
    /// </summary>
    /// <param name="original">密文</param>
    /// <returns>明文</returns>
    public static string Decrypt(string original)
    {
      return Decrypt(original,"sharejs.com",System.Text.Encoding.Default);
    }

    #endregion

    #region 使用 给定密钥字符串 加密/解密string
    /// <summary>
    /// 使用给定密钥字符串加密string
    /// </summary>
    /// <param name="original">原始文字</param>
    /// <param name="key">密钥</param>
    /// <param name="encoding">字符编码方案</param>
    /// <returns>密文</returns>
    public static string Encrypt(string original, string key)
    {
      byte[] buff = System.Text.Encoding.Default.GetBytes(original);
      byte[] kb = System.Text.Encoding.Default.GetBytes(key);
      return Convert.ToBase64String(Encrypt(buff,kb));
    }
    /// <summary>
    /// 使用给定密钥字符串解密string
    /// </summary>
    /// <param name="original">密文</param>
    /// <param name="key">密钥</param>
    /// <returns>明文</returns>
    public static string Decrypt(string original, string key)
    {
      return Decrypt(original,key,System.Text.Encoding.Default);
    }

    /// <summary>
    /// 使用给定密钥字符串解密string,返回指定编码方式明文
    /// </summary>
    /// <param name="encrypted">密文</param>
    /// <param name="key">密钥</param>
    /// <param name="encoding">字符编码方案</param>
    /// <returns>明文</returns>
    public static string Decrypt(string encrypted, string key,Encoding encoding)
    {
      byte[] buff = Convert.FromBase64String(encrypted);
      byte[] kb = System.Text.Encoding.Default.GetBytes(key);
      return encoding.GetString(Decrypt(buff,kb));
    }
    #endregion

    #region 使用 缺省密钥字符串 加密/解密/byte[]
    /// <summary>
    /// 使用缺省密钥字符串解密byte[]
    /// </summary>
    /// <param name="encrypted">密文</param>
    /// <param name="key">密钥</param>
    /// <returns>明文</returns>
    public static byte[] Decrypt(byte[] encrypted)
    {
      byte[] key = System.Text.Encoding.Default.GetBytes("sharejs.com");
      return Decrypt(encrypted,key);
    }
    /// <summary>
    /// 使用缺省密钥字符串加密
    /// </summary>
    /// <param name="original">原始数据</param>
    /// <param name="key">密钥</param>
    /// <returns>密文</returns>
    public static byte[] Encrypt(byte[] original)
    {
      byte[] key = System.Text.Encoding.Default.GetBytes("sharejs.com");
      return Encrypt(original,key);
    }
    #endregion

    #region 使用 给定密钥 加密/解密/byte[]

    /// <summary>
    /// 生成MD5摘要
    /// </summary>
    /// <param name="original">数据源</param>
    /// <returns>摘要</returns>
    public static byte[] MakeMD5(byte[] original)
    {
      MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
      byte[] keyhash = hashmd5.ComputeHash(original);
      hashmd5 = null;
      return keyhash;
    }

    /// <summary>
    /// 使用给定密钥加密
    /// </summary>
    /// <param name="original">明文</param>
    /// <param name="key">密钥</param>
    /// <returns>密文</returns>
    public static byte[] Encrypt(byte[] original, byte[] key)
    {
      TripleDESCryptoServiceProvider des = new TripleDESCryptoServiceProvider();
      des.Key = MakeMD5(key);
      des.Mode = CipherMode.ECB; 

      return des.CreateEncryptor().TransformFinalBlock(original, 0, original.Length);
    } 

    /// <summary>
    /// 使用给定密钥解密数据
    /// </summary>
    /// <param name="encrypted">密文</param>
    /// <param name="key">密钥</param>
    /// <returns>明文</returns>
    public static byte[] Decrypt(byte[] encrypted, byte[] key)
    {
      TripleDESCryptoServiceProvider des = new TripleDESCryptoServiceProvider();
      des.Key = MakeMD5(key);
      des.Mode = CipherMode.ECB; 

      return des.CreateDecryptor().TransformFinalBlock(encrypted, 0, encrypted.Length);
    } 

    #endregion

  }
}

代码三：

using System;
using System.Collections.Generic;
using System.Text; 

namespace MyLibs.encrypt
{
  public class Base64
  {
    private static string base64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";//编码后的字符集
    private static int[] base64DecodeChars = new int[] { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1 };//对应ASICC字符的位置
    public static string base64encode(string str)
    { //加密
      string Out = "";
      int i = 0, len = str.Length;
      char c1, c2, c3;
      while (i < len)
      {
        c1 = Convert.ToChar(str[i++] & 0xff);
        if (i == len)
        {
          Out += base64EncodeChars[c1 >> 2];
          Out += base64EncodeChars[(c1 & 0x3) << 4];
          Out += "==";
          break;
        }
        c2 = str[i++];
        if (i == len)
        {
          Out += base64EncodeChars[c1 >> 2];
          Out += base64EncodeChars[((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4)];
          Out += base64EncodeChars[(c2 & 0xF) << 2];
          Out += "=";
          break;
        }
        c3 = str[i++];
        Out += base64EncodeChars[c1 >> 2];
        Out += base64EncodeChars[((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4)];
        Out += base64EncodeChars[((c2 & 0xF) << 2) | ((c3 & 0xC0) >> 6)];
        Out += base64EncodeChars[c3 & 0x3F];
      }
      return Out;
    }
    public string utf16to8(string str)
    {
      string Out = "";
      int i, len;
      char c;//char为16位Unicode字符,范围0~0xffff,感谢vczh提醒
      len = str.Length;
      for (i = 0; i < len; i++)
      {//根据字符的不同范围分别转化
        c = str[i];
        if ((c >= 0x0001) && (c <= 0x007F))
        {
          Out += str[i];
        }
        else if (c > 0x07FF)
        {
          Out += (char)(0xE0 | ((c >> 12) & 0x0F));
          Out += (char)(0x80 | ((c >> 6) & 0x3F));
          Out += (char)(0x80 | ((c >> 0) & 0x3F));
        }
        else
        {
          Out += (char)(0xC0 | ((c >> 6) & 0x1F));
          Out += (char)(0x80 | ((c >> 0) & 0x3F));
        }
      }
      return Out;
    } 

    public static string base64decode(string str)
    {//解密
      int c1, c2, c3, c4;
      int i, len;
      string Out;
      len = str.Length;
      i = 0; Out = "";
      while (i < len)
      {
        do
        {
          c1 = base64DecodeChars[str[i++] & 0xff];
        } while (i < len && c1 == -1);
        if (c1 == -1) break;
        do
        {
          c2 = base64DecodeChars[str[i++] & 0xff];
        } while (i < len && c2 == -1);
        if (c2 == -1) break;
        Out += (char)((c1 << 2) | ((c2 & 0x30) >> 4));
        do
        {
          c3 = str[i++] & 0xff;
          if (c3 == 61) return Out;
          c3 = base64DecodeChars[c3];
        } while (i < len && c3 == -1);
        if (c3 == -1) break;
        Out += (char)(((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2));
        do
        {
          c4 = str[i++] & 0xff;
          if (c4 == 61) return Out;
          c4 = base64DecodeChars[c4];
        } while (i < len && c4 == -1);
        if (c4 == -1) break;
        Out += (char)(((c3 & 0x03) << 6) | c4);
      }
      return Out;
    } 

    public string utf8to16(string str)
    {
      string Out = "";
      int i, len;
      char c, char2, char3;
      len = str.Length;
      i = 0; while (i < len)
      {
        c = str[i++];
        switch (c >> 4)
        {
          case 0:
          case 1:
          case 2:
          case 3:
          case 4:
          case 5:
          case 6:
          case 7: Out += str[i - 1]; break;
          case 12:
          case 13: char2 = str[i++];
            Out += (char)(((c & 0x1F) << 6) | (char2 & 0x3F)); break;
          case 14: char2 = str[i++];
            char3 = str[i++];
            Out += (char)(((c & 0x0F) << 12) | ((char2 & 0x3F) << 6) | ((char3 & 0x3F) << 0)); break;
        }
      }
      return Out;
    } 

  }
} 

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