User System on Main Site

[Arrangements]

I've made the hard choice to have my site's user system synchronize with my vb forum users.

I'm creating the registration page right now on my main site; and I've hit a dead end.

I came to this:

PHP Code:

$encpass = sha1( SALT . $password ); 


I'v defined it:

PHP Code:

define('SALT', 'something'); 


So my question of problem is, wouldn't the password be encrypted differently on vb then on my mainsite? How does vb encrypt their passwords?

Edit: Okay after doing some searching, I found this

PHP Code:

md5(md5($password) . $salt); 


to be the way vb hash's up the password. Right? Correct me if I'm wrong.

And then $salt needs needs to pulled from vb's database to check the password on my mainsite.

Now here comes the 2nd part Cookies?

Originally Posted by https://vborg.vbsupport.ru/showthread.php?t=98047

$_COOKIE:
{cookiepfx}userid - plain(userid)
{cookiepfx}password - md5(md5(md5('PlaintextPassword') . salt) . 'LicenseNo').

Why is it does it use md5() 3 times?

Does that mean when I authenticate their cookie information I need to say.. 'reverse the md5()' once and then I can SELECT?