phc-discussions - Re: [PHC] Why protect against side channel attacks

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Thu, 25 Jun 2015 10:26:16 +0300
From: Solar Designer <solar@...nwall.com>
To: discussions@...sword-hashing.net
Subject: Re: [PHC] Why protect against side channel attacks

On Thu, Jun 25, 2015 at 03:06:08PM +0800, Ben Harris wrote:
> On 25 June 2015 at 14:25, Solar Designer <solar@...nwall.com> wrote:
> 
> > In fact, to fully defeat the attack, it is sufficient to have s or h;
> > it is not necessary to have both.  (In practice, it may be helpful to
> > have both for other reasons.)
> 
> 'h' being preferred over 's', as a system without 'h' would still leak
> password information as identical passwords would have the same
> side-channel data.

You're right.  Thank you for correcting me.

Side-channels aside, there are other good reasons why per-hash salts are
important to have even in presence of a system-wide secret.

Alexander