Re: [TLS] Should we require compressed points

[Eric Rescorla <[e-mail]>]

On Wed, Oct 22, 2014 at 8:15 PM, Andrei Popov <[e-mail]>
wrote:

>  A few considerations:
>
> -          The “IPR has expired” statement will require legal validation
> before an implementer can bake point compression into products;
>
> -          Fewer bytes on the wire/more CPU is a good tradeoff in some
> scenarios, but probably not in every scenario;
>
> -          Requiring support for point compression imposes additional
> (even if relatively minor, in the scale of things) cost for TLS1.3
> implementers.
>
>
>
> What are the reasons for getting rid of uncompressed points?
>
>
Really what I want is to get rid of point negotiation, because it's yet
another
point of complexity and it's not universally implemented anyway. Given that
people seem to think that compressed points are better, I figured that was
the way to go. If people prefer to just require uncompressed points (at
least for the existing X9.63 curves) I could certainly live with that.

-Ekr


>
>

>

>
 Cheers,
>
>
>
> Andrei
>
>
>
> *From:* TLS [mailto:[e-mail]] *On Behalf Of *Eric Rescorla
> *Sent:* Tuesday, October 21, 2014 7:52 AM
> *To:* [e-mail]
> *Subject:* [TLS] Should we require compressed points
>
>
>
> https://github.com/tlswg/tls13-spec/issues/80
>
>
>
> Today we discussed the possibility of requiring support for compressed
> points
>
> in TLS 1.3 now that the IPR has expired.
>
>
>
> Specifically, I propose that for TLS 1.3, we:
>
>
>
> - Use only compressed points for the existing curves (and presumably
>
>   whatever superior format is defined for the CFRG-recommended
>
>   curves, as appropriate).
>
>
>
> - Deprecate the Supported Point Formats extension for TLS 1.3
>
>
>
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>
> For RFC 4492-bis, we might also consider requiring support for compressed
>
> points as well as uncompressed (already required) but this seems like a
>
> separable issue, since it's mostly in service of optimization rather than
>
> simplicity.
>
>
>
> What do people think?
>
> -Ekr
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