I wanted to use Ward's code but did'nt work on server2003, the old _StringEncrypt is not RC4, the one that comes now I can't use in win98, so here is a port. Could not find one in the forums. This should act just like Ward's, but a thousand times slower.
#include "RC4.au3"
Local $p = 'key'
Local $d = ', lots of data'
$d = $d & $d;&$d&$d&$d&$d&$d&$d&$d&$d&$d&$d&$d&$d&$d
Local $t = TimerInit()
$Encrypt = _RC4($d, $p)
ConsoleWrite("1 ward $Encrypt >" & $Encrypt & "<" & @CRLF)
$Decrypt = _RC4($Encrypt, $p)
ConsoleWrite(