> > I am aware of a company that has instituted a policy that limits a > specific character in people's passwords to being a numeric character. > Personally, I am confused at this policy. It seems to me that > placing such a specific limit on a specific position in a password > simply reduces the number of guesses that someone would have to try > in a brute force attack. > > Does anyone out there know if there is any theoretical basis for > believing that a policy to limit a specific character position > in passwords to a numeric character will enhance security. If not, > does anyone know how such a misunderstanding might have occurred? Theoretically, you are right. The number of possible passwords is smaller with a limitation to a certain class of characters. In practice though, it might make sense if you consider psychological reasons: If a user is allowed to chose a password without any digits, then she will use a simple word in most cases. Seen from the other side: Making the passwords a bit more complicated gives you a slightly better protection against manual brute-forcing. To have a more satisfactory solution, you could make your system use cracklib or similar to check the strength of a new password. It will be bitching at you then. > Adrian Roman. -- - - | Roman Drahtmüller <draht@suse.de> // "You don't need eyes to see, | SuSE Linux AG - Security Phone: // you need vision!" | Nürnberg, Germany +49-911-740530 // Maxi Jazz, Faithless | - -
