Other algorithms may have too big certificates

[wbl]

[Ben] Requiring the signing certificate to be sent in every packet means that some algorithms will not be usable, since their certificates won’t fit, and probably also means it won’t be possible to fit more than one signature in the same packet (though I am not sure there’s a need for this). It might be sensible to instead send a hash of the certificate and have a separate way to request certificates which can then be cached.

[dansarie]

Since the current version of Roughtime will only use Ed25519, this won't become a problem. See also #39.