PHP的加密和解密程序方法

{

srand((double)microtime()*1000000);

$encrypt_key=md5(rand(0,32000));

$ctr=0;

$tmp="";

for($i=0;$i<strlen($txt);$i++)

{

if($ctr==strlen($encrypt_key))$ctr=0;

$tmp.=substr($encrypt_key,$ctr,1).

(substr($txt,$i,1)^substr($encrypt_key,$ctr,1));

$ctr++;

}

returnkeyED($tmp,$key);

}

functiondecrypt($txt,$key)

{

$txt=keyED($txt,$key);

$tmp="";

for($i=0;$i<strlen($txt);$i++)

{

$md5=substr($txt,$i,1);

$i++;

$tmp.=(substr($txt,$i,1)^$md5);

}

return$tmp;

}

$string="HelloWorld!!!";

//encrypt$string,andstoreitin$enc_text

$enc_text=encrypt($string,$key);

//decrypttheencryptedtext$enc_text,andstoreitin$dec_text

$dec_text=decrypt($enc_text,$key);

print"Originaltext:$string<Br>\n";

print"Encryptedtext:$enc_text<Br>\n";

print"Decryptedtext:$dec_text<Br>\n";

?>