Re: [TLS] Point Compression

I propose a method to compress NIST curves as defined in
https://tools.ietf.org/id/draft-jivsov-ecc-compact-05.html

Its main benefit is that the compressed point fits into field size / group
order size. There is no additional byte needed.

This encoding is enabled by by modifying key generation. If key generation
code can be changed, the adjustment is one bignum subtraction. If key
generation is a black box, e.g. as if it is done by an HSM, we generate
another key pair until conditions are met.

On average, adjustment is needed every second key generation.

No adjustment is needed for ECDH.

The method is solely based on published books and research papers from the
past century.

I hope this helps.

On Fri, Jul 30, 2021 at 9:48 AM Carl Mehner <c@cem.me> wrote:

> As requested during ekr's presentation
> <https://youtu.be/SfuvB41YhyU?t=980>, I will volunteer to write up a
> draft for defining new "supported groups" for compressed NIST curves. I
> didn't see/hear any objections during the tls-wg meeting, but thought
> I should probably confirm on the list before I got too far along in writing
> it...
>
> -carl
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