Re: [Cfrg] Point format endian (was: Adoption of draft-ladd-spake2 as a RG document)
"Dan Harkins" <dharkins@lounge.org> Tue, 27 January 2015 17:30 UTC
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Date: Tue, 27 Jan 2015 09:30:44 -0800
From: Dan Harkins <dharkins@lounge.org>
To: Watson Ladd <watsonbladd@gmail.com>
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Subject: Re: [Cfrg] Point format endian (was: Adoption of draft-ladd-spake2 as a RG document)
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On Tue, January 27, 2015 9:07 am, Watson Ladd wrote: > > My SPAKE2 draft contains specified M&N, generated by a C program > Nathan McCullum sent me. I've been unable to determine what that > program does in anything more than the vaguest terms because OpenSSL > internals are opaque, but users do not need to generate their own > points. Yes, it's opaque to you, the application writer. That's the point! But to have curve25519 as a special case then you'd have to pry into the opacity of the code and figure out what's going on. So to allow Nathan McCullum to send you a chunk of code that should work with any curve supported by OpenSSL, and have it just work without you knowing any opaque internals, it requires a canonical conversion of bitstring to integer to field element and back. If, as you say, users do not need to generate their own points then they're gonna have to have a registry of M and N for all curves. And to import a bitstring (for instance from the appendix of your draft) into code requires converting that bitstring into an element. And without the canonical conversion then you need to know about the opaque internals. Thank you for illustrating my point so well! Dan.
- 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