Re: [openpgp] SHA3 algorithm ids.
Daniel Kahn Gillmor <dkg@fifthhorseman.net> Tue, 11 August 2015 16:14 UTC
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From: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
To: Peter Gutmann <pgut001@cs.auckland.ac.nz>, Phillip Hallam-Baker <phill@hallambaker.com>, Derek Atkins <derek@ihtfp.com>
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References: <87y4hmi19i.fsf@vigenere.g10code.de> <7540C7A9-2830-4A63-8310-B684796DA279@nohats.ca> <55C681FC.9010100@iang.org> <sjma8tztbgo.fsf@securerf.ihtfp.org> <CAMm+Lwj7SxXTn+KD-eQSeZHwJB36tCgD1t0bodVsp3ovOaZ8mw@mail.gmail.com> <9A043F3CF02CD34C8E74AC1594475C73F4AD7C72@uxcn10-5.UoA.auckland.ac.nz>
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Date: Tue, 11 Aug 2015 12:14:11 -0400
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Cc: IETF OpenPGP <openpgp@ietf.org>, ianG <iang@iang.org>
Subject: Re: [openpgp] SHA3 algorithm ids.
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On Tue 2015-08-11 09:21:07 -0400, Peter Gutmann wrote: > What's the clear need for -512? By which I mean a demonstrated practical need > for a hash size of 64 bytes, not a hypothesised need given an imaginary > attack. I can see a need for SHA-256 (to replace SHA-1), but for something > like SHA3-512 all I can see are downsides (compared to SHA2-256). Is your concern CPU time or bandwidth (network/storage) or something else? If it's CPU time: on some architectures SHA-512 implementations are faster than SHA-256 implementations (except for digests of very short messages): 0 dkg@alice:~$ openssl speed sha512 sha256 Doing sha256 for 3s on 16 size blocks: 9475191 sha256's in 3.00s Doing sha256 for 3s on 64 size blocks: 5366754 sha256's in 3.00s Doing sha256 for 3s on 256 size blocks: 2344003 sha256's in 3.00s Doing sha256 for 3s on 1024 size blocks: 715128 sha256's in 3.00s Doing sha256 for 3s on 8192 size blocks: 96700 sha256's in 3.00s Doing sha512 for 3s on 16 size blocks: 7094449 sha512's in 3.00s Doing sha512 for 3s on 64 size blocks: 7048926 sha512's in 3.00s Doing sha512 for 3s on 256 size blocks: 2764993 sha512's in 3.00s Doing sha512 for 3s on 1024 size blocks: 972785 sha512's in 3.00s Doing sha512 for 3s on 8192 size blocks: 136283 sha512's in 3.00s OpenSSL 1.0.2d 9 Jul 2015 built on: reproducible build, date unspecified options:bn(64,64) rc4(16x,int) des(idx,cisc,16,int) aes(partial) blowfish(idx) compiler: gcc -I. -I.. -I../include -fPIC -DOPENSSL_PIC -DOPENSSL_THREADS -D_REENTRANT -DDSO_DLFCN -DHAVE_DLFCN_H -m64 -DL_ENDIAN -g -O2 -fstack-protector-strong -Wformat -Werror=format-security -D_FORTIFY_SOURCE=2 -Wl,-z,relro -Wa,--noexecstack -Wall -DMD32_REG_T=int -DOPENSSL_IA32_SSE2 -DOPENSSL_BN_ASM_MONT -DOPENSSL_BN_ASM_MONT5 -DOPENSSL_BN_ASM_GF2m -DSHA1_ASM -DSHA256_ASM -DSHA512_ASM -DMD5_ASM -DAES_ASM -DVPAES_ASM -DBSAES_ASM -DWHIRLPOOL_ASM -DGHASH_ASM -DECP_NISTZ256_ASM The 'numbers' are in 1000s of bytes per second processed. type 16 bytes 64 bytes 256 bytes 1024 bytes 8192 bytes sha256 50534.35k 114490.75k 200021.59k 244097.02k 264055.47k sha512 37837.06k 150377.09k 235946.07k 332043.95k 372143.45k 0 dkg@alice:~$ extra speed is hardly a downside. :) --dkg
- [openpgp] SHA3 algorithm ids. Werner Koch
- Re: [openpgp] SHA3 algorithm ids. Paul Wouters
- Re: [openpgp] SHA3 algorithm ids. Phillip Hallam-Baker
- Re: [openpgp] SHA3 algorithm ids. ianG
- Re: [openpgp] SHA3 algorithm ids. Phillip Hallam-Baker
- Re: [openpgp] SHA3 algorithm ids. ianG
- Re: [openpgp] SHA3 algorithm ids. Christoph Anton Mitterer
- Re: [openpgp] SHA3 algorithm ids. Phillip Hallam-Baker
- Re: [openpgp] SHA3 algorithm ids. ianG
- Re: [openpgp] SHA3 algorithm ids. Werner Koch
- Re: [openpgp] SHA3 algorithm ids. Peter Gutmann
- Re: [openpgp] SHA3 algorithm ids. Christoph Anton Mitterer
- Re: [openpgp] SHA3 algorithm ids. Stephen Farrell
- Re: [openpgp] SHA3 algorithm ids. ianG
- Re: [openpgp] SHA3 algorithm ids. Derek Atkins
- Re: [openpgp] SHA3 algorithm ids. Phillip Hallam-Baker
- Re: [openpgp] SHA3 algorithm ids. Werner Koch
- Re: [openpgp] SHA3 algorithm ids. ianG
- Re: [openpgp] SHA3 algorithm ids. Paul Wouters
- Re: [openpgp] SHA3 algorithm ids. Phillip Hallam-Baker
- Re: [openpgp] SHA3 algorithm ids. Peter Gutmann
- Re: [openpgp] SHA3 algorithm ids. Phillip Hallam-Baker
- [openpgp] Why or why not SHA{2,3}-512 (was: SHA3 … Werner Koch
- [openpgp] WWhy or why not SHA{2,3}-512 (was: SHA3… Werner Koch
- Re: [openpgp] SHA3 algorithm ids. Werner Koch
- Re: [openpgp] SHA3 algorithm ids. Werner Koch
- Re: [openpgp] SHA3 algorithm ids. Daniel Kahn Gillmor
- Re: [openpgp] SHA3 algorithm ids. Daniel Kahn Gillmor
- Re: [openpgp] SHA3 algorithm ids. Peter Gutmann
- [openpgp] SHA-x performance (was: SHA3 algorithm … Werner Koch
- Re: [openpgp] SHA-x performance (was: SHA3 algori… Daniel Kahn Gillmor
- Re: [openpgp] SHA-x performance (was: SHA3 algori… Peter Gutmann
- Re: [openpgp] SHA-x performance (was: SHA3 algori… Dang, Quynh
- Re: [openpgp] SHA-x performance Werner Koch
- Re: [openpgp] SHA3 algorithm ids. ianG
- Re: [openpgp] SHA-x performance Werner Koch
- Re: [openpgp] Why or why not SHA{2, 3}-512 (was: … Phillip Hallam-Baker
- Re: [openpgp] SHA-x performance Peter Gutmann
- Re: [openpgp] Why or why not SHA{2, 3}-512 Werner Koch
- Re: [openpgp] SHA-x performance ianG
- Re: [openpgp] SHA-x performance Phillip Hallam-Baker
- Re: [openpgp] SHA3 algorithm ids. Derek Atkins
- Re: [openpgp] SHA-x performance ianG
- Re: [openpgp] SHA3 algorithm ids. Phillip Hallam-Baker
- Re: [openpgp] SHA-x performance Bill Frantz
- Re: [openpgp] SHA-x performance Hilarie Orman
- Re: [openpgp] WWhy or why not SHA{2, 3}-512 (was:… Phillip Hallam-Baker
- Re: [openpgp] SHA-x performance NIIBE Yutaka
- Re: [openpgp] SHA3 algorithm ids. Derek Atkins
- Re: [openpgp] SHA-x performance Peter Gutmann
- Re: [openpgp] SHA3 algorithm ids. Bill Frantz
- Re: [openpgp] SHA3 algorithm ids. ianG
- Re: [openpgp] SHA3 algorithm ids. Derek Atkins
- Re: [openpgp] SHA3 algorithm ids. Bill Frantz
- Re: [openpgp] SHA3 algorithm ids. Phillip Hallam-Baker
- Re: [openpgp] SHA3 algorithm ids. Peter Gutmann
- Re: [openpgp] SHA3 algorithm ids. Andrey Jivsov
- Re: [openpgp] SHA3 algorithm ids. ianG
- Re: [openpgp] SHA3 algorithm ids. Robert J. Hansen
- Re: [openpgp] SHA3 algorithm ids. Werner Koch