Re: [Cfrg] Point format endian
"Derek Atkins" <derek@ihtfp.com> Tue, 27 January 2015 16:26 UTC
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Date: Tue, 27 Jan 2015 11:25:54 -0500
From: Derek Atkins <derek@ihtfp.com>
To: Paul Hoffman <paul.hoffman@vpnc.org>
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Subject: Re: [Cfrg] Point format endian
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Paul, On Tue, January 27, 2015 11:07 am, Paul Hoffman wrote: > We do not need "consensus" in this RG, just assurance that what we > recommend does not have security holes. No one has suggested any security > holes based on the endianness. The argument that "using different math > would add code" is true, but pretty much irrelevant relative the to the > size of the code needed to add a new curve. There is no interoperability > issue: if someone messes up the math in either endian direction, they will > know the first time they test their code, and there is approximately > 2^-128 chance that if they got it wrong and only tested one vector, that > they will accidentally get a good result. > > The longer we argue about our preferences (instead of actual security > issues), the worse off the IETF is. It is important for interoperability. If I tell you that my ECC Public Key is 0102030405060708090a but you interpret that as 0a090807060504030201 -- we will get different results even if both of us implement the math correctly. So I would argue that transmission encoding of keys and results *is* a matter of security. Then of course there's the matter of using the shared secret in another algorithm, like AES. Again, byte-order differences would result in different AES keys. Yet another matter of security. Yes, it just mean we just need to "choose one". But for the last 20+ years we've already chosen: network-byte-order. > --Paul Hoffman -derek -- Derek Atkins 617-623-3745 derek@ihtfp.com www.ihtfp.com Computer and Internet Security Consultant
- Re: [Cfrg] Point format endian (was: Adoption of … Dan Brown
- Re: [Cfrg] Point format endian (was: Adoption of … Peter Gutmann
- Re: [Cfrg] Point format endian (was: Adoption of … Alyssa Rowan
- Re: [Cfrg] Point format endian (was: Adoption of … Alyssa Rowan
- Re: [Cfrg] Point format endian (was: Adoption of … Michael Clark
- Re: [Cfrg] Point format endian (was: Adoption of … Michael Clark
- Re: [Cfrg] Point format endian (was: Adoption of … Watson Ladd
- Re: [Cfrg] Point format endian (was: Adoption of … Michael Clark
- Re: [Cfrg] Point format endian (was: Adoption of … Peter Gutmann
- Re: [Cfrg] Point format endian (was: Adoption of … Stephen Farrell
- Re: [Cfrg] Point format endian (was: Adoption of … Peter Gutmann
- Re: [Cfrg] Point format endian (was: Adoption of … Alyssa Rowan
- Re: [Cfrg] Point format endian (was: Adoption of … Stephen Farrell
- Re: [Cfrg] Point format endian (was: Adoption of … Peter Gutmann
- Re: [Cfrg] Point format endian (was: Adoption of … Stephen Farrell
- Re: [Cfrg] Point format endian (was: Adoption of … Salz, Rich
- Re: [Cfrg] Point format endian Derek Atkins
- Re: [Cfrg] Point format endian Salz, Rich
- Re: [Cfrg] Point format endian Stephen Farrell
- Re: [Cfrg] Point format endian Paul Hoffman
- Re: [Cfrg] Point format endian Derek Atkins
- Re: [Cfrg] Point format endian Derek Atkins
- Re: [Cfrg] Point format endian Blumenthal, Uri - 0558 - MITLL
- Re: [Cfrg] Point format endian Paul Hoffman
- Re: [Cfrg] Point format endian Watson Ladd
- Re: [Cfrg] Point format endian (was: Adoption of … Dan Harkins
- Re: [Cfrg] Point format endian (was: Adoption of … Watson Ladd
- Re: [Cfrg] Point format endian (was: Adoption of … Andy Lutomirski
- Re: [Cfrg] Point format endian (was: Adoption of … Dan Harkins
- Re: [Cfrg] Point format endian (was: Adoption of … Stephen Farrell
- Re: [Cfrg] Point format endian Tony Arcieri
- Re: [Cfrg] Point format endian (was: Adoption of … Michael Clark
- Re: [Cfrg] Point format endian Damien Miller
- Re: [Cfrg] Point format endian Phillip Hallam-Baker
- Re: [Cfrg] Point format endian Phillip Hallam-Baker
- Re: [Cfrg] Point format endian (was: Adoption of … Watson Ladd
- Re: [Cfrg] Point format endian (was: Adoption of … D. J. Bernstein
- Re: [Cfrg] Point format endian (was: Adoption of … Dan Harkins
- Re: [Cfrg] Point format endian (was: Adoption of … Watson Ladd