Re: reducing our reliance on MD5

On Tue, Feb 10, 2015 at 4:21 PM, Robert Haas <robertmhaas@gmail.com> wrote:
> Although the patch was described as relatively easy to write, it never
> went anywhere, because it *replaced* MD5 authentication with bcrypt,
> which would be a big problem for existing clients.  It seems clear
> that we should add something new and not immediately kill off what
> we've already got, so that people can transition smoothly.  An idea I
> just had today is to keep using basically the same system that we are
> currently using for MD5, but with a stronger hash algorithm, like
> SHA-1 or SHA-2 (which includes SHA-224, SHA-256, SHA-384, and
> SHA-512).  Those are slower, but my guess is that even SHA-512 is not
> enough slower for anybody to care very much, and if they do, well
> that's another reason to make use of the new stuff optional.

I believe that a big advantage of bcrypt for authentication is the
relatively high memory requirements. This frustrates GPU based
attacks.


-- 
Peter Geoghegan