From: Brian Candler <B.Candler@...>
Date: 2003-05-30T17:41:48+09:00
Subject: Re: [Q]: CGI::Session

On Fri, May 30, 2003 at 10:38:41AM +0900, Tom Danielsen wrote:
> As far as I know any 64-bit part of the hash is as good as any
> other.  But why not use the full 128-bit hash?  Performance?
> I modified session.rb to use the full hash, and it seems to
> work ok.  (Better collision resistance).

If you are using 64 bit hashes, then you need to have about 2^32 concurrent
sessions to get a reasonably high chance of a collision. That's quite a lot
of sessions :-)