I might sound like a nitpicker, but there's a very important distinction
between "encryption" and "hashing".
The gist of this difference is the following:
Encryption is designed to be reversible - of course you'll need the
correct key. You can always decrypt something that is encrypted.
Hashing it designed to be NOT reversible - you can only get a hash by
providing the proper input. Hashing is usually used for a safe password
storage (usually together with a "Salt" value, to make it harder to
check against a list of precalculated hashes). It's not possible to
"decrypt" a hash - though if the hash algorithm itself has weaknesses,
you might be able to generate some other input which gives to same hash
value (this is known as a "Collision").
There are nice Wikipedia articles on both:
http://en.wikipedia.org/wiki/Encryption
http://en.wikipedia.org/wiki/Hash_function
I do not actually know what kind of algorithm i5/OS uses.
I do _ASSUME_ that a QPWDLVL of 0 or 1 use a really old form of password
storage - maybe even single DES encryption with a key known to all
i5/OS, OS/400 instance (this is only a guess). And that QPWDLVL of 2 and
3 use a secure, modern Hash Algorithm for password storage (like SHA1 or
MD5). Some of the QPWDLVL values also remove the legacy LM hashes (a
very insecure method) from the User Profile. As said, these are all
ASSUMPTIONS. They MIGHT be true, but they probably aren't.
-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[
mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Steve Landess
Sent: Monday, July 02, 2007 10:55 PM
To: midrange-l@xxxxxxxxxxxx
Subject: Where are the System i password storeds?
All -
I'm having a "discussion" with another developer right now about where
AS/400 - iSeries - System i passwords are stored.
He says that they are stored in a file - I say that they are encrypted
and stored within the user profile.
Who is right?
Is there an IBM link that discusses this information somewhere on their
web site?
Regards,
Steve Landess
Austin, Texas
All animals are equal but some animals are more equal than others.
- George Orwell
midrange.com
