Re: md5 again

On Tue, 11 Jul 2000, Bruce Momjian wrote:

> > > > If CL sends the MD5 of the username rather than the plaintext username,
> > > > only CL and PG will know what the username is.  PG will know it by 
> > > > comparing it with the MD5 of every username in pg_shadow. So even if the
> > > > wire is being sniffed the unhashed username can be used in the password's
> > > > encryption along with the salt sent by PG.  This method will take longer
> > > > for a user to log in, but the login process is only per session, not per
> > > > SQL call.  
> > > 
> > > A linear search of pg_shadow to log in is not acceptable; we don't want
> > > to make login any slower than we have to.  I see no real gain in security
> > > from doing this anyway...
> > 
> > By knowing what PG will do with the username and random salt, sniffing 
> > the wire can make guessing the password trivial.  If the username was
> > never sent over the wire in the clear the unhashed username is an unknown
> > salt to he who is sniffing.  But it's true that it would introduce a
> > slower than necessary login.
> > 
> 
> Does it?  I thought it was the password being run through MD5 that made
> it secure.

Simple dictionary passwords.  Run them thru a script and compare the 
output.  

Vince.
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