From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.3 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI,RCVD_IN_SORBS_SPAM, RP_MATCHES_RCVD,T_DKIM_INVALID shortcircuit=no autolearn=no autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 81A142013E for ; Thu, 2 Mar 2017 22:35:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751657AbdCBWfi (ORCPT ); Thu, 2 Mar 2017 17:35:38 -0500 Received: from mail-it0-f47.google.com ([209.85.214.47]:36483 "EHLO mail-it0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751553AbdCBWfg (ORCPT ); Thu, 2 Mar 2017 17:35:36 -0500 Received: by mail-it0-f47.google.com with SMTP id h10so2676179ith.1 for ; Thu, 02 Mar 2017 14:34:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc; bh=ogUiU8tCCUZfecPGS7+oBCR3UC5VWumtUkp+k7emlRY=; b=RT2THmr2Qxz055w4jaq18TrpZrrQyCIMVWtW+PLC6KbygU86jV6w9lwvGizZeyFbrd 7Ac6bzBeKb4hnUBH75jBAGaHACLbgs/24M+0tAoEtWmnUbPk0uWW0Da1ZHWVT/7mV3cs 9WzoPQtQQcmpCGpd1GcXKZfhWn5W1vel26KFmH9cBvqquwTLeCzyRJB8fMZMU9WZj5sY d3OSXctGoLKT9b9f94m7tCEYwmyjQlCNanKtxfwmQLmVNaQoUyrbxnKR163Dnw2qJ8af 6aK7GvCAfHufz0VFilvevHwjs+pKWh5JMgop5PI4IXn3HerG7LuQhGEjXTDv7j47YErZ QWxg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:cc; bh=ogUiU8tCCUZfecPGS7+oBCR3UC5VWumtUkp+k7emlRY=; b=Zb8ndepGKoufm/W4nXPSbZOkIxToUdpK9H0bWvToJb79oVg21gyhL+IaQ8Xm6mL/rJ bO3sdp9b+cZV0q0c4S9dcZVIS92dfeuufHnCPqpjOOxcOkyxwz4WGPA/sa1jeiWYmi4g b3X2RBQ2osukwVjRVU8yjMzByG2q8raVbZ/uvm0T8efCZNvYTmf1TSKqDvwjkPToQ3zC EUCDw/DKrsL+CdngsMeYVYVrmEiSsNDdyTwbVKldv044Hzrntykueq68IxWONYXEkjc6 c1FgyzyCmHeiwXdSMIqH7ZfL6utYwQPPjObpY5AqIYsIs0c6fin1pKnpl/F3KsvZh62U 9XYw== X-Gm-Message-State: AMke39llv/eAmCkzVtdomzpq0zFRBoOBKu9MiYtqHDE/Lu3tcA7iM8lGkJLOhNdd9QB3Fl1/d8Vll7kt8+R7+w== X-Received: by 10.36.66.141 with SMTP id i135mr120232itb.86.1488493635906; Thu, 02 Mar 2017 14:27:15 -0800 (PST) MIME-Version: 1.0 Received: by 10.107.146.131 with HTTP; Thu, 2 Mar 2017 14:27:15 -0800 (PST) In-Reply-To: <20170302215457.l2zhxgnvhulw2hl5@kitenet.net> References: <20170223164306.spg2avxzukkggrpb@kitenet.net> <22704.19873.860148.22472@chiark.greenend.org.uk> <20170224233929.p2yckbc6ksyox5nu@sigill.intra.peff.net> <20170302215457.l2zhxgnvhulw2hl5@kitenet.net> From: Linus Torvalds Date: Thu, 2 Mar 2017 14:27:15 -0800 X-Google-Sender-Auth: za0g_Szn8UTfHFe8bzLO3UMquYY Message-ID: Subject: Re: SHA1 collisions found To: Joey Hess Cc: Junio C Hamano , Jeff King , Ian Jackson , Git Mailing List Content-Type: text/plain; charset=UTF-8 Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Thu, Mar 2, 2017 at 1:54 PM, Joey Hess wrote: > > There's a surprising result of combining iterated hash functions, that > the combination is no more difficult to attack than the strongest hash > function used. Duh. I should actually have known that. I started reading the paper and went "this seems very familiar". I'm pretty sure I've been pointed at that paper before (or maybe just a similar one), and I just didn't react enough for it to leave a lasting impact. Linus