From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752448Ab3LPEWv (ORCPT ); Sun, 15 Dec 2013 23:22:51 -0500 Received: from science.horizon.com ([71.41.210.146]:29709 "HELO science.horizon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752240Ab3LPEWu (ORCPT ); Sun, 15 Dec 2013 23:22:50 -0500 Date: 15 Dec 2013 23:22:47 -0500 Message-ID: <20131216042247.9826.qmail@science.horizon.com> From: "George Spelvin" To: linux@horizon.com, tytso@mit.edu Subject: Re: Replace /dev/random input mix polynomial with Brent's xorgen? Cc: linux-kernel@vger.kernel.org In-Reply-To: <20131215221948.GA6773@thunk.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Dec 15, 2013 at 03:34:59AM -0500, George Spelvin wrote: >> You're describing standard key-recovery attacks. For /dev/random, >> just knowing the *ciphertext* constitutes a successful attack. > Um, no. The *ciphertext* is the output. The attacker can get all of > the ciphertext he or she wants by reading /dev/random (although we'd > probably do some folding as we currently do so the attacker won't even > get all of the ciphertext). What the attacker has to be able to do is > given some of the ciphertext bits, be able to predict future > ciphertext bits given some construction which uses AES as the basis. The attack I was thinking of was figuring out (without breaking root and using ptrace) what some *other* process on the same machine is reading from /dev/random. In other words, reading someone else's output.