php 加密解密类(含公钥)的实现代码_PHP教程

php
class crypt{
// 本文来源：龙哥博客
protected $key = “”; //公钥

private function keyed($txt,$encrypt_key)
{
$encrypt_key = md5($encrypt_key);
$ctr=0;
$tmp = “”;
for ($i=0;$i{
if ($ctr==strlen($encrypt_key)){
$ctr=0;
}
$tmp.= substr($txt,$i,1) ^ substr($encrypt_key,$ctr,1);
$ctr++;
}
return $tmp;
}

public function encrypt($txt,$key=”")
{
if(empty($key)){
$key=$this->key;
}
srand((double)microtime()*1000000);
$encrypt_key = md5(rand(0,32000));
$ctr=0;
$tmp = “”;
for ($i=0;$i{
if ($ctr==strlen($encrypt_key)){
$ctr=0;
}
$tmp.= substr($encrypt_key,$ctr,1) .
(substr($txt,$i,1) ^ substr($encrypt_key,$ctr,1));
$ctr++;
}
return $this->keyed($tmp,$key);
}

public function decrypt($txt,$key=”")
{
if(empty($key)){
$key=$this->key;
}

$txt = $this->keyed($txt,$key);
$tmp = “”;
for ($i=0;$i{
$md5 = substr($txt,$i,1);
$i++;
$tmp.= (substr($txt,$i,1) ^ $md5);
}
return $tmp;
}

public function setkey($key)
{
if(empty($key)){
return null;
}
$this->key=$key;
}

public function getkey()
{
return $this->key;
}
// downloads by http://www.bkjia.com
}
$string = “http://www.52blogger.com”;
$crypt= new crypt();
$crypt->setkey(“http://www.52blogger.com”);
$enc_text = $crypt->encrypt($string,$crypt->getkey());
$dec_text = $crypt->decrypt($enc_text,$crypt->getkey());
echo “加密前 : $string
\n”;
echo “加密后 : $enc_text
\n”;
echo “解密后 : $dec_text \n”;
?>

执行结果:

加密前 : http://www.52blogger.com
加密后 : hszq’z* kp~y(wpvs=6q3gzbr5qkhtz(f=zm
解密后 : http://www.52blogger.com

注意的是：每次加密后的字符串都不一样,另外还需要公钥才能解密,如果公钥不对,解密的结果与明文是不一致的.可惜的是,此方法貌似不支持中文~