On Wed, Apr 20, 2005 at 09:58:31PM -0400, Stephen Frost wrote: > * Greg Stark ([EMAIL PROTECTED]) wrote: > > Stephen Frost <[EMAIL PROTECTED]> writes: > > > I have some hopes that pointing out the rather large problem with the > > > md5 authentication mechanism in pg_hba.conf will lead them to discourage > > > it's use and thus reduce the occourances of the salt being made > > > available to the user giving more weight to the usefullness of having it > > > be a random salt. Additionally, it's been a few years, perhaps > > > viewpoints have changed. > > > > Salts are always given to the user, that's how they work. They're not > > secret. > > You're confusing the issues I'm afraid. If you're using md5 to secure > your transport then yes, you must provide the salt to the user since the > same salt must be used on both sides. That's not the salt under > discussion, however; the salt I'm referring to is the one which is used > to make it difficult to brute-force the password from a copy of the > resultant hash. That salt is not given to anyone because no one else > needs it- only the server needs to know that salt so that it can add it > to the password to compare against the hash in the database.
Something that just occured to me... if you're using a random salt, you can change it periodically without any disruption. So in the case of a site that's worried about brute-forcing a password or hash you can periodically update all the salts with new random values. The protocol could also send a nonce as part of the key exchange. I believe both techniques would add security. -- Jim C. Nasby, Database Consultant [EMAIL PROTECTED] Give your computer some brain candy! www.distributed.net Team #1828 Windows: "Where do you want to go today?" Linux: "Where do you want to go tomorrow?" FreeBSD: "Are you guys coming, or what?" ---------------------------(end of broadcast)--------------------------- TIP 7: don't forget to increase your free space map settings
