PHP初记｜xxtea类

xxtea可逆加密算法PHP实现：

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Class Xxtea {	public function encrypt($s, $key) {		return base64_encode(self :: xxtea_encrypt($s, $key));	}	public function decrypt($e, $key) {		return self :: xxtea_decrypt(base64_decode($e), $key);	}	private function long2str($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]);		}		if ($w) {			return substr(join('', $s), 0, $n);		} else {			return join('', $s);		}	}	private function str2long($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) $n;	}	private function xxtea_encrypt($str, $key) {		if ($str == "") {			return "";		}		$v = self :: str2long($str, true);		$k = self :: str2long($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--) {			$sum = self :: int32($sum + $delta);			$e = $sum >> 2 & 3;			for ($p = 0; $p < $n; $p++) {				$y = $v[$p +1];				$mx = self :: int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ self :: int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z));				$z = $v[$p] = self :: int32($v[$p] + $mx);			}			$y = $v[0];			$mx = self :: int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ self :: int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z));			$z = $v[$n] = self :: int32($v[$n] + $mx);		}		return self :: long2str($v, false);	}	private function xxtea_decrypt($str, $key) {		if ($str == "") {			return "";		}		$v = self :: str2long($str, false);		$k = self :: str2long($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));		$sum = self :: int32($q * $delta);		while ($sum != 0) {			$e = $sum >> 2 & 3;			for ($p = $n; $p > 0; $p--) {				$z = $v[$p -1];				$mx = self :: int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ self :: int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z));				$y = $v[$p] = self :: int32($v[$p] - $mx);			}			$z = $v[$n];			$mx = self :: int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ self :: int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z));			$y = $v[0] = self :: int32($v[0] - $mx);			$sum = self :: int32($sum - $delta);		}		return self :: long2str($v, true);	}}

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使用方法：

加密：

Xxtea::encrypt(明文字符串, 密钥字符串);

解密：

Xxtea::decrypt(密文字符串, 密钥字符串);

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