本文实例讲述了PHP实现的XXTEA加密解密算法。分享给大家供大家参考，具体如下：
<?php
/**
* Xxtea 加密实现类
*/
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);
}
}
//用法测试：
$strDemo = "www.jb51.net";
$key = "123456";
$pwd = new Xxtea();
$pwdrel = $pwd->encrypt($strDemo, $key);
echo $pwdrel;
echo "<br/>";
echo $pwd->decrypt($pwdrel, $key);
?>
运行结果：
{���H(�S��7*�u7U www.jb51.net
PS：关于加密解密感兴趣的朋友还可以参考本站在线工具：
在线RSA加密/解密工具： http://tools.jb51.net/password/rsa_encode
文字在线加密解密工具（包含AES、DES、RC4等）： http://tools.jb51.net/password/txt_encode
在线散列/哈希算法加密工具: http://tools.jb51.net/password/hash_encrypt
在线MD5/hash/SHA-1/SHA-2/SHA-256/SHA-512/SHA-3/RIPEMD-160加密工具： http://tools.jb51.net/password/hash_md5_sha
在线sha1/sha224/sha256/sha384/sha512加密工具： http://tools.jb51.net/password/sha_encode