PHP和C#可共用的可逆加密算法详解

<?php
class des
{
  var $key;
  var $iv; //偏移量
  
  function des($key = '11001100', $iv=0 ) {
  //key长度8例如:1234abcd
    $this->key = $key;
    if( $iv == 0 ) {
      $this->iv = $key; //默认以$key 作为 iv
    } else {
      $this->iv = $iv; //mcrypt_create_iv ( mcrypt_get_block_size (mcrypt_des, mcrypt_mode_cbc), mcrypt_dev_random );
    }
  }
  
  function encrypt($str) {
  //加密，返回大写十六进制字符串
    $size = mcrypt_get_block_size ( mcrypt_des, mcrypt_mode_cbc );
    $str = $this->pkcs5pad ( $str, $size );
    return strtoupper( bin2hex( mcrypt_cbc(mcrypt_des, $this->key, $str, mcrypt_encrypt, $this->iv ) ) );
  }
  
  function decrypt($str) {
  //解密
    $strbin = $this->hex2bin( strtolower( $str ) );
    $str = mcrypt_cbc( mcrypt_des, $this->key, $strbin, mcrypt_decrypt, $this->iv );
    $str = $this->pkcs5unpad( $str );
    return $str;
  }
  
  function hex2bin($hexdata) {
    $bindata = "";
    for($i = 0; $i < strlen ( $hexdata ); $i += 2) {
      $bindata .= chr ( hexdec ( substr ( $hexdata, $i, 2 ) ) );
    }
    return $bindata;
  }

  function pkcs5pad($text, $blocksize) {
    $pad = $blocksize - (strlen ( $text ) % $blocksize);
    return $text . str_repeat ( chr ( $pad ), $pad );
  }
  
  function pkcs5unpad($text) {
    $pad = ord ( $text {strlen ( $text ) - 1} );
    if ($pad > strlen ( $text ))
      return false;
    if (strspn ( $text, chr ( $pad ), strlen ( $text ) - $pad ) != $pad)
      return false;
    return substr ( $text, 0, - 1 * $pad );
  }
  
}
?>

using system;
using system.collections.generic;
using system.io;
using system.linq;
using system.security.cryptography;
using system.text;

namespace windowsformsapplication1
{
  /// <summary>
  /// des加密解密字符串
  /// </summary>
  public class desencryption
  {
    /// <summary>
    /// des加密字符串
    /// </summary>
    /// <param name="encryptstring">待加密的字符串</param>
    /// <param name="encryptkey">加密密钥,要求为8位</param>
    /// <returns>加密成功返回加密后的字符串，失败返回null</returns>
    public static string encryptdes(string encryptstring, string encryptkey = "11001100")
    {
      try
      {
        byte[] rgbkey = asciiencoding.ascii.getbytes(encryptkey.substring(0, 8));
        byte[] rgbiv = rgbkey;
        byte[] inputbytearray = encoding.utf8.getbytes(encryptstring);
        descryptoserviceprovider dcsp = new descryptoserviceprovider();
        memorystream mstream = new memorystream();
        cryptostream cstream = new cryptostream(mstream, dcsp.createencryptor(rgbkey, rgbiv), cryptostreammode.write);
        cstream.write(inputbytearray, 0, inputbytearray.length);
        cstream.flushfinalblock();
        stringbuilder ret = new stringbuilder();
        foreach (byte b in mstream.toarray())
        {
          ret.appendformat("{0:x2}", b);
        }
        ret.tostring();
        return ret.tostring(); 
      }
      catch
      {
        return null;
      }
    }

    /// <summary>
    /// des解密字符串
    /// </summary>
    /// <param name="decryptstring">待解密的字符串</param>
    /// <param name="decryptkey">解密密钥,要求为8位,和加密密钥相同</param>
    /// <returns>解密成功返回解密后的字符串，失败返回null</returns>
    public static string decryptdes(string decryptstring, string decryptkey = "11001100")
    {
      try
      {
        byte[] rgbkey = asciiencoding.ascii.getbytes(decryptkey);
        byte[] rgbiv = rgbkey;
        byte[] inputbytearray = new byte[decryptstring.length / 2];
        for (int x = 0; x < decryptstring.length / 2; x++)
        {
          int i = (convert.toint32(decryptstring.substring(x * 2, 2), 16));
          inputbytearray[x] = (byte)i;
        }      
        descryptoserviceprovider dcsp = new descryptoserviceprovider();
        memorystream mstream = new memorystream();
        cryptostream cstream = new cryptostream(mstream, dcsp.createdecryptor(rgbkey, rgbiv), cryptostreammode.write);
        cstream.write(inputbytearray, 0, inputbytearray.length);
        cstream.flushfinalblock();
        return encoding.utf8.getstring(mstream.toarray());
      }
      catch
      {
        return null;
      }
    }
  }
}