Re: [DNSOP] Whiskey Tango Foxtrot on key lengths...
Nicholas Weaver <nweaver@icsi.berkeley.edu> Tue, 01 April 2014 13:05 UTC
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From: Nicholas Weaver <nweaver@icsi.berkeley.edu>
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Date: Tue, 01 Apr 2014 06:05:20 -0700
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References: <0EA28BE8-E872-46BA-85FD-7333A1E13172@icsi.berkeley.edu> <53345C77.8040603@uni-due.de> <B7893984-2FAD-472D-9A4E-766A5C212132@pch.net> <102C13BE-E45E-437A-A592-FA373FF5C8F0@ogud.com>
To: Ólafur Guðmundsson <ogud@ogud.com>
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Archived-At: http://mailarchive.ietf.org/arch/msg/dnsop/74RwWcpv4yNcuzjIDkvnh3MnQZI
Cc: dnsop@ietf.org, Nicholas Weaver <nweaver@icsi.berkeley.edu>, Matthäus Wander <matthaeus.wander@uni-due.de>, Bill Woodcock <woody@pch.net>
Subject: Re: [DNSOP] Whiskey Tango Foxtrot on key lengths...
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On Apr 1, 2014, at 5:39 AM, Olafur Gudmundsson <ogud@ogud.com> wrote: > > Doing these big jumps is the wrong thing to do, increasing the key size increases three things: > time to generate signatures > bits on the wire > verification time. > > I care more about verification time than bits on the wire (as I think that is a red herring). > Signing time increase is a self inflicted wound so that is immaterial. > > sign verify sign/s verify/s > rsa 1024 bits 0.000256s 0.000016s 3902.8 62233.2 > rsa 2048 bits 0.001722s 0.000053s 580.7 18852.8 > rsa 4096 bits 0.012506s 0.000199s 80.0 5016.8 > > Thus doubling the key size decreases the verification performance by roughly by about 70%. > > KSK's verification times affect the time to traverse the DNS tree, thus > If 1024 is too short 1280 is fine for now > If 2048 is too short 2400 bit key is much harder to break thus it should be fine. > > just a plea for key use policy sanity not picking on Bill in any way. NO! FUCK THAT SHIT. Seriously. There is far far far too much worrying about "performance" of crypto, in cases like this where the performance just doesn't matter! Yes, you can only do 18K verifies per CPU per second for 2048b keys. Cry me a river. Bite the bullet, go to 2048 bits NOW, especially since the servers do NOT have resistance to roll-back-the-clock attacks. In a major cluster validating recursive resolver, like what Comcast runs with Nominum or Google uses with Public DNS, the question is not how many verifies it can do per second per CPU core, but how many verifies it needs to do per second per CPU core. And at the same time, this is a problem we already know how to parallelize, and which is obscenely parallel, and which also caches... Lets assume a typical day of 1 billion external lookups for a major ISP centralized resolver, and that all are verified. Thats less 1 CPU core-day to validate every DNSSEC lookup that day at 2048b keys. And yeah, DNS is peaky, but that's also why this task is being run on a cluster already, and each cluster node has a lot of CPUs. -- Nicholas Weaver it is a tale, told by an idiot, nweaver@icsi.berkeley.edu full of sound and fury, 510-666-2903 .signifying nothing PGP: http://www1.icsi.berkeley.edu/~nweaver/data/nweaver_pub.asc
- [DNSOP] Whiskey Tango Foxtrot on key lengths... Nicholas Weaver
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Nicholas Weaver
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Joe Abley
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Paul Hoffman
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Nicholas Weaver
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Rose, Scott
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Stephane Bortzmeyer
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Matthäus Wander
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Christopher Morrow
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Nicholas Weaver
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Christopher Morrow
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Paul Wouters
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Paul Wouters
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Joe Abley
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Joe Abley
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Bill Woodcock
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Tony Finch
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Colm MacCárthaigh
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Andrew Sullivan
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Tony Finch
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Joe Abley
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Thierry Moreau
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Matthäus Wander
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Joe Abley
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Colm MacCárthaigh
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… S Moonesamy
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Olafur Gudmundsson
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Bill Woodcock
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Nicholas Weaver
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Nicholas Weaver
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Jelte Jansen
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Mark Andrews
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Colm MacCárthaigh
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Mark Andrews
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Colm MacCárthaigh
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Olafur Gudmundsson
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Olafur Gudmundsson
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Paul Hoffman
- [DNSOP] CD (Re: Whiskey Tango Foxtrot on key leng… Evan Hunt
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Mark Andrews
- [DNSOP] CD bit (was Re: Whiskey Tango Foxtrot on … Andrew Sullivan
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Olafur Gudmundsson
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Colm MacCárthaigh
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Paul Wouters
- Re: [DNSOP] CD bit (was Re: Whiskey Tango Foxtrot… Mark Andrews
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Nicholas Weaver
- Re: [DNSOP] CD bit (was Re: Whiskey Tango Foxtrot… Andrew Sullivan
- Re: [DNSOP] CD (Re: Whiskey Tango Foxtrot on key … Colm MacCárthaigh
- Re: [DNSOP] CD (Re: Whiskey Tango Foxtrot on key … Nicholas Weaver
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- [DNSOP] Current DNSOP thread and why 1024 bits Edward Lewis
- Re: [DNSOP] Current DNSOP thread and why 1024 bits Nicholas Weaver
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Stephane Bortzmeyer
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Paul Hoffman
- Re: [DNSOP] Current DNSOP thread and why 1024 bits Paul Hoffman
- [DNSOP] mailing list behavior Re: Current DNSOP t… Suzanne Woolf
- Re: [DNSOP] Current DNSOP thread and why 1024 bits Colm MacCárthaigh
- Re: [DNSOP] Current DNSOP thread and why 1024 bits Paul Wouters
- Re: [DNSOP] Current DNSOP thread and why 1024 bits S Moonesamy
- Re: [DNSOP] Current DNSOP thread and why 1024 bits Paul Hoffman
- Re: [DNSOP] Current DNSOP thread and why 1024 bits Rose, Scott
- Re: [DNSOP] CD (Re: Whiskey Tango Foxtrot on key … Mark Andrews
- Re: [DNSOP] CD (Re: Whiskey Tango Foxtrot on key … Colm MacCárthaigh
- Re: [DNSOP] Current DNSOP thread and why 1024 bits S Moonesamy
- Re: [DNSOP] Current DNSOP thread and why 1024 bits David Conrad
- Re: [DNSOP] Current DNSOP thread and why 1024 bits Paul Wouters
- Re: [DNSOP] Current DNSOP thread and why 1024 bits Ben Laurie
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Francis Dupont