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Re: [Cfrg] Adoption of draft-ladd-spake2 as a RG document

"Dearlove, Christopher (UK)" <chris.dearlove@baesystems.com> Mon, 19 January 2015 11:56 UTC

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From: "Dearlove, Christopher (UK)" <chris.dearlove@baesystems.com>
To: Alexey Melnikov <alexey.melnikov@isode.com>, "cfrg@irtf.org" <cfrg@irtf.org>
Thread-Topic: [Cfrg] Adoption of draft-ladd-spake2 as a RG document
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Date: Mon, 19 Jan 2015 11:56:27 +0000
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Subject: Re: [Cfrg] Adoption of draft-ladd-spake2 as a RG document
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A minor point compared to choice of curve. Commenting on draft draft-agl-cfrgcurve-00, it indicates, in section 8 the use of little-endian order. RFC 5480 (obvious prior art in IETF) does not appear to specify big/little endianness, but delegates that to its reference SEC1. That document (http://www.secg.org/sec1-v2.pdf) in section 2.3.7 reverses the order of its x and M coefficients to produce a big-endian representation of an integer. Big endian format is also used by, for example, OpenSSL. Is the use of little endian format here a deliberate design decision?

-- 
Christopher Dearlove
Senior Principal Engineer, Information Assurance Group
Communications, Networks and Image Analysis Capability
BAE Systems Advanced Technology Centre
West Hanningfield Road, Great Baddow, Chelmsford, CM2 8HN, UK
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chris.dearlove@baesystems.com | http://www.baesystems.com

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