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Date: Wed, 6 May 2009 16:10:20 -0500
From: Matt Mackall <mpm@selenic.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
       "Eric W. Biederman" <ebiederm@xmission.com>,
       Arjan van de Ven <arjan@infradead.org>, Jake Edge <jake@lwn.net>,
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       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
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       Andrew Morton <akpm@linux-foundation.org>, Greg KH <greg@kroah.com>,
       Dave Jones <davej@redhat.com>
Subject: Re: [patch] random: make get_random_int() more random
Message-ID: <20090506211020.GE31071@waste.org>
References: <20090505063156.GA24504@elte.hu> <m14ow0ynjm.fsf@fess.ebiederm.org> <20090505195246.GC21973@elte.hu> <20090505202219.GL31071@waste.org> <20090506103034.GA25203@elte.hu> <20090506162543.GT31071@waste.org> <alpine.LFD.2.01.0905060942340.4983@localhost.localdomain> <20090506200954.GA21484@elte.hu> <20090506204156.GB31071@waste.org> <20090506205145.GA1908@elte.hu>
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On Wed, May 06, 2009 at 10:51:45PM +0200, Ingo Molnar wrote:
> Linus's patch is a marked improvement, and it is really what we need 
> here mostly.

No one's arguing that it isn't an improvement. But -15 years of
research- points to MD4 (let alone **half**MD4) being insufficient. To
counter that, two non-cryptanalysts have presented nothing beyond "it
seems strong enough to me" and "it passes a meaningless test". Pardon
me if I'm not satisfied by that.

> We cannot afford true physical randomness (it's too expensive to get 
> and not all hw has it), and even a 'good' PRNG is pretty expensive. 

And what of my suggestion (multiple times now) to replace halfMD4 with
SHA1? Or AES. Or any cryptographic primitive that's not known to be
completely worthless?

-- 
Mathematics is the supreme nostalgia of our time.