MT::Auth

=head2 MT::Auth->is_valid_password($author, $password, $crypted, \$error_ref)

A routine that determines whether the given password is valid for the
author object supplied. If the password is already processed by the
'crypt' function, the third parameter here will be positive. The \$error_ref
is a reference to a scalar variable for storing any error message to
be returned to the application. The routine itself should return 1 for
a valid password, 0 or undef for an invalid one.