OpenPGP: Implement EDDSA

[koto]

Bits and pieces are already present, i.e. the Ed25519 domain parameters, but the actual EDDSA is missing. GnuPG implements https://tools.ietf.org/html/draft-koch-eddsa-for-openpgp-00 with an algorithm ID = 22 and 1.3.6.1.4.1.11591.15.1 as a prime curve OID for Ed25519.

[sirdarckcat]

we added the OID, but that's it
bc31370

do you know if there are any samples? (eg test keys/messages)