From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [RFC PATCH 0/3] mtd: nand: add randomizer support Date: Thu, 1 May 2014 10:34:07 -0600 Message-ID: <20140501163407.GB3296@obsidianresearch.com> References: <1398906592-24677-1-git-send-email-b.brezillon.dev@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1398906592-24677-1-git-send-email-b.brezillon.dev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Boris BREZILLON Cc: Brian Norris , David Woodhouse , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Maxime Ripard , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org On Thu, May 01, 2014 at 03:09:49AM +0200, Boris BREZILLON wrote: > Hello, > > This series is a proposal to add support for randomizers (either software > or hardware) to NAND flash controller drivers. FWIW, I think the term for reversibly combining a PRBS with data is 'scrambling', it is often used in communication systems for similar reasons - probabilisticly increasing transition density. randomizing is something else entirely :) BTW, there are security concerns here. The scrambler PRBS must not be predictable by the user, otherwise they can write data that undoes the scramble and defeat it, ie deliberately writing the last 2k of a 4k write block as all 0's after scrambling could cause the first 2k to be lost. That feels like something that could be scary .. Jason -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html