From: utzoo!decvax!cca!gwyn@Brl@sri-unix
Newsgroups: net.unix-wizards
Title: Re:  efficiency of /etc/passwd lookup
Article-I.D.: sri-unix.4072
Posted: Wed Oct 27 05:06:50 1982
Received: Thu Oct 28 03:19:20 1982

From:     Doug Gwyn <gwyn@Brl>
Date:     25 Oct 82 11:00:11-EDT (Mon)
The BRL (JHU) UNIX used here has been modified to use a separate user-
information file, among many other similar system changes.  The encrypted
passwords have been moved to a less readable file, as you suggest.  I
would also like to urge the following:
	When the "passwd" program is run (automatically upon password
	aging, as implemented in newer Bell UNIXes, or manually when
	the user or system manager needs to change a password), it
	should ONLY allow passwords that pass the following tests:
	1)  certain minimum number of characters, etc. as recommended
	in the paper "Password Security:  A Case History";
	2)  not in the on-line dictionary;
	3)  not equal to the login name.
	Perhaps other security checks could be added, but these seem
	essential.
Given this more stringent password checking, there should be no problem
with the current readable encrypted "salted password" scheme.  Please
note that UNIX security does not seem to be tight enough for classified
Defense work (does anyone know what the outcome of the "Kernelized Secure
UNIX" project was?).

Yes, let's get at the password through the library interface rather than
directly.  The less known about file formats the better off a system
utility is when the formats change.  Apparently Berkeley is going to
make us all change the way we search directories anyway...