Re: reducing our reliance on MD5 - Mailing list pgsql-hackers

From Robert Haas
Subject Re: reducing our reliance on MD5
Date
Msg-id CA+TgmoZNS7D-pbTG4oUHaYoGWSO3D8g=MB5XsRFhd8mDoUmFdg@mail.gmail.com
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In response to Re: reducing our reliance on MD5  (Peter Geoghegan <pg@heroku.com>)
Responses Re: reducing our reliance on MD5  (Peter Eisentraut <peter_e@gmx.net>)
List pgsql-hackers
On Tue, Feb 10, 2015 at 7:32 PM, Peter Geoghegan <pg@heroku.com> wrote:
> 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.

I don't actually care which algorithm we use, and I dowannahafta care.
What I do want to do is provide a framework so that, when somebody
discovers that X is better than Y because Z, somebody who knows about
cryptography and not much about PostgreSQL ca add support for X in a
relatively small number of lines of code.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company



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