feature: support gpg keys (with subkeys!)

[jessefarinacci]

Thanks for making the command line glorious.

It'd really rock if melt would support the correct-horse-battery-staple-ification of GPG keys in addition to the subset of SSH keys it supports currently.

What a win for good security hygiene on the internet, if we could have GPG keys with SSH subkeys all safely protected with a classic Charm ui/ux win for ease of use and simplification.... :-)

Please close if out of scope.

[taciturnaxolotl]

i don't know quite enough about GPG to give a definitive answer but from a bit of research it looks like you can't fully construct a GPG key from seed material alone since it has non-deterministic components (creation timestamps, key IDs, UIDs, subkey binding signatures) that can't be reconstructed from seed material alone. It also wouldn't be feasible to encode the raw key in BIP39 since that is limited to 128-256 bytes and GPG keys are upwards of 1200 bits.