PHP加密解密

yanjing5462

?php
$key = "www.my55.com.cn";
function keyED($txt,$encrypt_key)
{
$encrypt_key = md5($encrypt_key);
$ctr=0;
$tmp = "";
for ($i=0;$istrlen($txt);$i++)
{
if ($ctr==strlen($encrypt_key)) $ctr=0;
$tmp.= substr($txt,$i,1) ^ substr($encrypt_key,$ctr,1);
$ctr++;
}
return $tmp;
}
function encrypt($txt,$key)
{
srand((double)microtime()*1000000);
$encrypt_key = md5(rand(0,32000));
$ctr=0;
$tmp = "";
for ($i=0;$istrlen($txt);$i++)
{
if ($ctr==strlen($encrypt_key)) $ctr=0;
$tmp.= substr($encrypt_key,$ctr,1) .
(substr($txt,$i,1) ^ substr($encrypt_key,$ctr,1));
$ctr++;
}
return keyED($tmp,$key);
}
function decrypt($txt,$key)
{
$txt = keyED($txt,$key);
$tmp = "";
for ($i=0;$istrlen($txt);$i++)
{
$md5 = substr($txt,$i,1);
$i++;
$tmp.= (substr($txt,$i,1) ^ $md5);
}
return $tmp;
}
$string = "近年来，由于我国经济的发展过多依赖了投资拉动，投资过热的现象已经给经济未来的发展留下很多隐患，经济发展存在的问题很多。";
// encrypt $string, and store it in $enc_text
$enc_text = encrypt($string,$key);
// decrypt the encrypted text $enc_text, and store it in $dec_text
$dec_text = decrypt($enc_text,$key);
print "Original text : $string
";
print "Encrypted text : $enc_text
";
print "Decrypted text : $dec_text
";
?>


本文来自ChinaUnix博客，如果查看原文请点：http://blog.chinaunix.net/u/2326/showart_193018.html