From: Herbert Xu Subject: Re: [BUGFIX] crypto: Fix ctr(aes) testing by specifying geniv Date: Fri, 14 Aug 2009 11:05:27 +1000 Message-ID: <20090814010527.GA1653@gondor.apana.org.au> References: <1249285483-22286-1-git-send-email-ying.huang@intel.com> <20090805094506.GA12528@gondor.apana.org.au> <1249524767.24238.318.camel@yhuang-dev.sh.intel.com> <1250044020.5337.214.camel@yhuang-dev.sh.intel.com> <20090813045300.GA19993@gondor.apana.org.au> <20090813073910.GA21784@gondor.apana.org.au> <20090813131253.GA27289@gondor.apana.org.au> <1250211667.5337.288.camel@yhuang-dev.sh.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "linux-kernel@vger.kernel.org" , "linux-crypto@vger.kernel.org" To: Huang Ying Return-path: Received: from rhun.apana.org.au ([64.62.148.172]:45839 "EHLO arnor.apana.org.au" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752005AbZHNBF2 (ORCPT ); Thu, 13 Aug 2009 21:05:28 -0400 Content-Disposition: inline In-Reply-To: <1250211667.5337.288.camel@yhuang-dev.sh.intel.com> Sender: linux-crypto-owner@vger.kernel.org List-ID: On Fri, Aug 14, 2009 at 09:01:07AM +0800, Huang Ying wrote: > > I see seqiv is used in rfc3686 mode, it means seqiv can not be used on > raw counter mode but can be used for rfc3686? Yeah, with rfc3686 a portion of the counter is available for counting bytes within each request. This allows a sequential IV to be safely used as each IV is essentially 2^32 blocks apart. With raw counter mode as soon as you process two blocks in one request the next IV would collide with one that has alreay been used. Cheers, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt