<?php/** * Xxtea 加密實現類 */class xxtea {  private function long2str($v, $w) {    $len = count($v);    $n = ($len -1) << 2;    if ($w) {      $m = $v[$len -1];      if (($m < $n -3) || ($m > $n))        return false;      $n = $m;    }    $s = array ();    for ($i = 0; $i < $len; $i++)      $s[$i] = pack("V", $v[$i]);    return $w ? substr(implode('', $s), 0, $n) : implode('', $s);  }  private function str2long($s, $w) {    $v = unpack("V*", $s . str_repeat("/0", (4 - strlen($s) % 4) & 3));    $v = array_values($v);    if ($w)      $v[count($v)] = strlen($s);    return $v;  }  private function int32($n) {    while ($n >= 2147483648)      $n -= 4294967296;    while ($n <= 2147483649)      $n += 4294967296;    return (int) $n;  }  public function encrypt($str, $key) {    if ($str == '')      return '';    $v = $this->str2long($str, true);    $k = $this->str2long($key, false);    if (count($k) < 4)      for ($i = count($k); $i < 4; $i++)        $k[$i] = 0;    $n = count($v) - 1;    $z = $v[$n];    $y = $v[0];    $delta = 0x9E3779B9;    $q = floor(6 + 52 / ($n +1));    $sum = 0;    while (0 < $q--) {      $sum = $this->int32($sum + $delta);      $e = $sum >> 2 & 3;      for ($p = 0; $p < $n; $p++) {        $y = $v[$p +1];        $mx = $this->int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ $this->int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z));        $z = $v[$p] = $this->int32($v[$p] + $mx);      }      $y = $v[0];      $mx = $this->int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ $this->int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z));      $z = $v[$n] = $this->int32($v[$n] + $mx);    }    return $this->long2str($v, false);  }  public function decrypt($str, $key) {    if ($str == '')      return '';    $v = $this->str2long($str, false);    $k = $this->str2long($key, false);    if (count($k) < 4)      for ($i = count($k); $i < 4; $i++)        $k[$i] = 0;    $n = count($v) - 1;    $z = $v[$n];    $y = $v[0];    $delta = 0x9E3779B9;    $q = floor(6 + 52 / ($n +1));    $sum = $this->int32($q * $delta);    while ($sum != 0) {      $e = $sum >> 2 & 3;      for ($p = $n; $p > 0; $p--) {        $z = $v[$p -1];        $mx = $this->int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ $this->int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z));        $y = $v[$p] = $this->int32($v[$p] - $mx);      }      $z = $v[$n];      $mx = $this->int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ $this->int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z));      $y = $v[0] = $this->int32($v[0] - $mx);      $sum = $this->int32($sum - $delta);    }    return $this->long2str($v, true);  }}//用法測試：$strDemo = "www.49028c.com";$key = "123456";$pwd = new Xxtea();$pwdrel = $pwd->encrypt($strDemo, $key);echo $pwdrel;echo "<br/>";echo $pwd->decrypt($pwdrel, $key);?>