Comment by antonb2011

Not so. If it's a 4 digit combination, it's already n!, so 24 combinations, which is enough for a good system to lock up and automatically call the police. If it's more, then it's gonna grow as n!/k!l!m!... where, k, l, m... are the numbers of repeated digits, but still it's more than enough to know that someone's trying to brute force the system.