On Sun, Mar 2, 2014 at 4:20 PM, Andreas Schildbach <andreas@schildbach.de> wrote:

I somehow think that it is too early for this heavy kind of extension,
given that the first version of BIP70 isn't even deployed widely let
alone *used*.

Definitely agree - like I said, I publish this only because I keep getting asked about it.

By reading your proposal I get the idea that the current spec doesn't
allow two (or three) different PKIs at once

That's right. There's little point in having multiple PKI's simultaneously, that's why it doesn't allow it.

This one is a special case because it doesn't replace but rather specialises and extends the existing PKI. Old clients that don't understand it would still show something useful and by upgrading you get better output. Actually you get closer to the output you're supposed to get.

That's going to be rare though, I think. Generally you wouldn't want to have multiple PKIs in use simultaneously for the same payment request.

I would prefer if your fix would stay local to X.509 (and thus only
change X.509 specific structs rather than the top-level PaymentRequest).

It can be done but only by sacrificing backwards compatibility, which doesn't seem worth it to me. It's hardly a big deal to have two signature fields. The rest is all localised to the X509 parts.