Do complex passwords actually accomplish anything?
Posted: Wed Jul 15, 2009 11:36 am
Link to paper found here.
An interesting read. They do a pretty good jerb of covering the related theory and math as well without getting too far off topic.tfa wrote:We find that traditional password advice given to users
is somewhat dated. Strong passwords do nothing to
protect online users from password stealing attacks such
as phishing and keylogging, and yet they place consid-
erable burden on users. Passwords that are too weak of
course invite brute-force attacks. However, we ¯nd that
relatively weak passwords, about 20 bits or so, are suf-
¯cient to make brute-force attacks on a single account
unrealistic so long as a \three strikes" type rule is in
place. Above that minimum it appears that increasing
password strength does little to address any real threat.
If a larger credential space is needed it appears better
to increase the strength of the userID's rather than the
passwords. For large institutions this is just as e®ective
in deterring bulk guessing attacks and is a great deal
better for users. For small institutions there appears
little reason to require strong passwords for online ac-
counts.