On Sat, Aug 31, 2002 at 11:37:04AM -0700, Jeremy C. Reed wrote:
> On Sat, 31 Aug 2002, Tamas TEVESZ wrote:
> > now. if i get access to the stored hashes, what exactly makes me
> > unable to re-use them ?
> That wasn't the point. And I understand what you mean. The purpose was
> simply to not have the passwords stored in plain text. (I believe security
> by obscurity is a valid addition to already existing security.)
The problem with what you describe is that the hashes become authentication
equivalent tokens. The idea of storing plaintext passwords orginally was
that you then weren't storing auth equivalent tokens. In fact, when you
store passwords hashed, you make it into a harder problem, by the fact that
you include extra text, a salt.
I believe there are ways of doing what you describe,
http://www-cs-students.stanford.edu/~tjw/srp/
appears to have the right properties, kerberos also.
Perhaps you should investigate using one of these in your vm-pop3d. I
haven't looked in detail, and you shouldn't trust it blindly, but if
you can search for papers on it, you may get some idea of what the
cryptography community think of it.
MBM
--
Matthew Byng-Maddick <mbm@???> http://colondot.net/
