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[104.178.186.189]) by smtp.gmail.com with ESMTPSA id 3f1490d57ef6-e1d04181167sm1105725276.10.2024.09.05.10.04.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Sep 2024 10:04:35 -0700 (PDT) Date: Thu, 5 Sep 2024 13:04:34 -0400 From: Taylor Blau To: Junio C Hamano Cc: Jeff King , "brian m. carlson" , git@vger.kernel.org, Elijah Newren , Patrick Steinhardt Subject: Re: [PATCH 0/4] hash.h: support choosing a separate SHA-1 for non-cryptographic uses Message-ID: References: <20240905103736.GC2556395@coredump.intra.peff.net> Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On Thu, Sep 05, 2024 at 09:51:00AM -0700, Junio C Hamano wrote: > Taylor Blau writes: > > > If so, I agree, but would note that this series does not yet switch > > index-pack to use the non-collision detecting SHA-1 implementation when > > available, so that would not be a prerequisite for merging this series. > > Hmph, I am confused. It needs to be corrected in order to address > collisions of the tail sum Peff raised, as no longer checked the > tail sum with SHA1DC but with "fast" SHA-1. Peff's mail supposes that we have already modified index-pack to use the non-collision detecting SHA-1 implementation. But this series does not do that, so I don't think we have an issue to address here. In a hypothetical future series where we do modify index-pack to use the _FAST SHA-1 implementation, then we would need to address the issue that Peff raised first as a prerequisite. Thanks, Taylor