From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Subject: Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in
 place of MD5
Date: Thu, 22 Dec 2016 16:53:20 +0100
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Cc: kernel-hardening@lists.openwall.com,
        "Theodore Ts'o" <tytso@mit.edu>,
        Andy Lutomirski <luto@amacapital.net>,
        Netdev <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
        David Laight <David.Laight@aculab.com>,
        Eric Dumazet <edumazet@google.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Eric Biggers <ebiggers3@gmail.com>,
        Tom Herbert <tom@herbertland.com>,
        Andi Kleen <ak@linux.intel.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>
To: Hannes Frederic Sowa <hannes@stressinduktion.org>
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On Thu, Dec 22, 2016 at 4:51 PM, Hannes Frederic Sowa
<hannes@stressinduktion.org> wrote:
> This algorithm should be a non-seeded algorithm, because the hashes
> should be stable and verifiable by user space tooling. Thus this would
> need a hashing algorithm that is hardened against pre-image
> attacks/collision resistance, which siphash is not. I would prefer some
> higher order SHA algorithm for that actually.

Right. SHA-256, SHA-512/256, Blake2s, or Blake2b would probably be
good candidates for this.