PHP加密解密实例分析

本文实例讲述了PHP加密解密方法。分享给大家供大家参考，具体如下：

    //加密
    function string2secret($str)
    {
     $key = "123";
     $td = mcrypt_module_open(MCRYPT_DES,'','ecb','');
     $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
     $ks = mcrypt_enc_get_key_size($td);
     $key = substr(md5($key), 0, $ks);
     mcrypt_generic_init($td, $key, $iv);
     $secret = mcrypt_generic($td, $str);
     mcrypt_generic_deinit($td);
     mcrypt_module_close($td);
     return $secret;
    }
    //解密
    function secret2string($sec)
    {
     $key = "123";
     $td = mcrypt_module_open(MCRYPT_DES,'','ecb','');
     $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
     $ks = mcrypt_enc_get_key_size($td);
     $key = substr(md5($key), 0, $ks);
     mcrypt_generic_init($td, $key, $iv);
     $string = mdecrypt_generic($td, $sec);
     mcrypt_generic_deinit($td);
     mcrypt_module_close($td);
     return trim($string);
    }
    echo secret2string(string2secret("11111111111111111"));
    //显示结果是11111111111111111
    echo '<br>'.string2secret("11111111111111111");
    //显示乱码
    echo '<br>';
    //$string:要加密的字符串 $isEncrypt=true:加密 $isEncrypt=false:解密
    function dencrypt($string, $isEncrypt = true, $key = "KEY_SPACE") {
     if (!isset($string{0}) || !isset($key{0})) {
      return false;
     }
     $dynKey = $isEncrypt ? hash('sha1', microtime(true)) : substr($string, 0, 40);
     $fixedKey = hash('sha1', $key);
     $dynKeyPart1 = substr($dynKey, 0, 20);
     $dynKeyPart2 = substr($dynKey, 20);
     $fixedKeyPart1 = substr($fixedKey, 0, 20);
     $fixedKeyPart2 = substr($fixedKey, 20);
     $key = hash('sha1', $dynKeyPart1 . $fixedKeyPart1 . $dynKeyPart2 . $fixedKeyPart2);
     $string = $isEncrypt ? $fixedKeyPart1 . $string . $dynKeyPart2 : (isset($string{339}) ? gzuncompress(base64_decode(substr($string, 40))) : base64_decode(substr($string, 40)));
     $n = 0;
     $result = '';
     $len = strlen($string);
     for ($n = 0; $n < $len; $n++) {
      $result .= chr(ord($string{$n}) ^ ord($key{$n % 40}));
     }
     return $isEncrypt ? $dynKey . str_replace('=', '', base64_encode($n > 299 ? gzcompress($result) : $result)) : substr($result, 20, -20);
    }
    echo strlen(dencrypt("12345678912345"));

希望本文所述对大家PHP程序设计有所帮助。