Re: pg_authid.rolpassword format (was Re: [HACKERS] Password identifiers, protocol aging and SCRAM protocol)

On 14 December 2016 20:12:05 EET, Bruce Momjian <bruce@momjian.us> wrote:
>On Wed, Dec 14, 2016 at 11:27:15AM +0100, Magnus Hagander wrote:
>> I would so like to just drop support for plain passwords completely
>:) But
>> there's a backwards compatibility issue to think about of course.
>> 
>> But -- is there any actual usecase for them anymore?
>
>I thought we recommended 'password' for SSL connections because if you
>use MD5 passwords the password text layout is known and that simplifies
>cryptanalysis.

No, that makes no sense. And whether you use 'password' or 'md5' authentication is a different question than whether
youstore passwords in plaintext or as md5 hashes. Magnus was asking whether it ever makes sense to *store* passwords in
plaintext.

Since you brought it up, there is a legitimate argument to be made that 'password' authentication is more secure than
'md5',when SSL is used. Namely, if an attacker can acquire contents of pg_authid e.g. by stealing a backup tape, with
'md5'authentication he can log in as any user, using just the stolen hashes. But with 'password', he needs to reverse
thehash first. It's not a great difference, but it's something.
 
- Heikki