Again: decrypt/encrypt with winNT/2K

[kgahn]

Hi,

I've followed up your discussion about decrypting/encrypting strings with NT OS in the back.

you've given a lot of solutions how to avoid a 2way encryption. but no solution for it with php on win32 systems.

aren't there any? I mean - these 2way-encryption syntaxes are implemented in php, but only don't work on win32.

but what if you want to encrypt a cookie before storing it on the local machine? if you want to use the cookie context later - you have(!) to decrypt it to continue using theses values!

so can anyone give me a solution for php4/win2000 that uses a 2way-cipher algorithm?

TIA
Karsten

[Anon]

Not sure if this is what you need, but it might suffice. It's a snippet of code I found on the PHP.net site under md5 (I think)...I forget the author. It works great on NT, and the author calls it triple RMD5 or something.

HTH

$key1 = "This would be key #1";
$key2 = "This would be key #2";
$key3 = "This would be key #3";
$text = "This would be the string to have encrypted";
function keygen($input,$crypted) {
$crypted=md5($crypted);
$ctr=0;
$keyresult="";
for($i=0;$i<strlen($input);$i++) {
if($ctr==strlen($crypted)) $ctr=0;
$keyresult.=substr($input,$i,1)^{substr($crypted,$ctr,1);}
$ctr++;
}
return $keyresult;
}
function encrypt($input,$cryptkey) {
srand((double)microtime()*1000000);
$encrypted=md5(rand(0,32000));
$ctr=0;
$keyresult="";
for ($i=0;$i<strlen($input);$i++) {
if ($ctr==strlen($encrypted)) $ctr=0;
$keyresult.=substr($encrypted,$ctr,1).(substr($input,$i,1)^{substr($encrypted,$ctr,1));}
$ctr++;
}
return keygen($keyresult,$cryptkey);
}
function decrypt($input,$cryptkey) {
$input=keygen($input,$cryptkey);
$keyresult="";
for ($i=0;$i<strlen($input);$i++) {
$md5=substr($input,$i,1);
$i++;
$keyresult.=(substr($input,$i,1)^$md5);
}
return $keyresult;
}
$enc=base64_encode(keygen(encrypt(keygen($text,$key1),$key2),$key3));
$dec=keygen(decrypt(keygen(base64_decode($enc),$key3),$key2),$key1);