Horton

Re: SCRAM salt length

Heikki Linnakangas <hlinnaka@iki.fi>

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From: Heikki Linnakangas <hlinnaka@iki.fi>
To: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Robert Haas <robertmhaas@gmail.com>, Michael Paquier <michael.paquier@gmail.com>
Cc: Aleksander Alekseev <a.alekseev@postgrespro.ru>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2017-08-17T16:10:09Z
Lists: pgsql-hackers 
On 08/17/2017 05:23 PM, Peter Eisentraut wrote:
> On 8/17/17 09:21, Heikki Linnakangas wrote:
>> The RFC doesn't say anything about salt
>> length, but the one example in it uses a 16 byte string as the salt.
>> That's more or less equal to the current default of 12 raw bytes, after
>> base64-encoding.
> 
> The example is
> 
>     S: r=rOprNGfwEbeRWgbNEkqO%hvYDpWUa2RaTCAfuxFIlj)hNlF$k0,
>        s=W22ZaJ0SNY7soEsUEjb6gQ==,i=4096
> 
> That salt is 24 characters and 16 raw bytes.

Ah, I see, that's from the SCRAM-SHA-256 spec. I was looking at the 
example in the original SCRAM-SHA-1 spec:

S: r=fyko+d2lbbFgONRv9qkxdawL3rfcNHYJY1ZVvWVs7j,s=QSXCR+Q6sek8bf92,
       i=4096

- Heikki

Commits

  1. Increase SCRAM salt length

  2. Make SCRAM salts and nonces longer.