Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758770AbcLPTsc (ORCPT ); Fri, 16 Dec 2016 14:48:32 -0500 Received: from mail-qk0-f179.google.com ([209.85.220.179]:36835 "EHLO mail-qk0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754502AbcLPTsW (ORCPT ); Fri, 16 Dec 2016 14:48:22 -0500 MIME-Version: 1.0 In-Reply-To: References: <20161216034618.28276.qmail@ns.sciencehorizons.net> From: Tom Herbert Date: Fri, 16 Dec 2016 11:47:35 -0800 Message-ID: Subject: Re: [PATCH v5 1/4] siphash: add cryptographically secure PRF To: "Jason A. Donenfeld" Cc: Jean-Philippe Aumasson , George Spelvin , Andi Kleen , David Miller , David Laight , Eric Biggers , Hannes Frederic Sowa , kernel-hardening@lists.openwall.com, Linux Crypto Mailing List , LKML , Andy Lutomirski , Netdev , Linus Torvalds , "Theodore Ts'o" , vegard.nossum@gmail.com, "Daniel J . Bernstein" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 875 Lines: 26 On Fri, Dec 16, 2016 at 4:39 AM, Jason A. Donenfeld wrote: > Hey JP, > > On Fri, Dec 16, 2016 at 9:08 AM, Jean-Philippe Aumasson > wrote: >> Here's a tentative HalfSipHash: >> https://github.com/veorq/SipHash/blob/halfsiphash/halfsiphash.c >> >> Haven't computed the cycle count nor measured its speed. > Tested this. Distribution and avalanche effect are still good. Speed wise I see about a 33% improvement over siphash (20 nsecs/op versus 32 nsecs). That's about 3x of jhash speed (7 nsecs). So that might closer to a more palatable replacement for jhash. Do we lose any security advantages with halfsiphash? Tom > This is incredible. Really. Wow! > > I'll integrate this into my patchset and will write up some > documentation about when one should be used over the other. > > Thanks again. Quite exciting. > > Jason