[nemo1618]

Is RSA mandatory for your use case? Both PGP and TLS support ECC, right?

[grammarxcore]

You are correct that the specs support ECC. Go's implementation is not complete (see https://godoc.org/golang.org/x/crypto/openpgp/packet). More importantly you can't guarantee clients will be able to use ECC. See this issue (from my initial link): https://github.com/golang/go/issues/20058