Login Generator gotcha

One for the archive:

Validation on a new password submission [/signup] was less than 30
characters [validates_length_of helper] but the resulting hash in the
database was more than 30 [c40] â?? the result was that in a relation JOIN
that users the User model, the password *hash validates_length_of the
hash [and not the original textual password] which silently fails and
doesnt save the record…

There’s a couple of solutions - anyone want to have a shot at it?