xxtea加密解密算法的PHP实现

ispsh

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);  
}  
}  
　　说明：

　　encrypt(明文字符串, 密钥字符串);