I have an X509 certificate (chain) and private key in PEM format. I need to convert them to GPG format so I can use them for signing. How can I do that?
I tried gpgsm, but the keys still don't appear on gpg list of keys.
Please, advise.
It’s separate key storage: gpg has ~/.gnupg/pubring.gpg, gpgsm has ~/.gnupg/pubring.kbx
So keys added with gpgsm aren’t usable with gpg; gpg doesn’t read ~/.gnupg/pubring.kbx.
To see they keys you added with gpgsm, use gpgsm --list-keys. And to create ciphertext from those gpgsm keys, use gpgsm --encrypt. And so on. It’s a completely separate tool from gpg.
As far as importing X.509 stuff for use by gpg, GnuPG doesn’t provide a way to do that. There’s nothing in the OpenPGP standard about it, so there’s no interoperable way to do it.
But the commercial (Symantec) PGP Desktop tool has some way of doing it, so if you can get ahold of a copy of PGP Desktop, I guess you could use that to import your X.509 stuff into PGP Desktop’s key storage, then export it as a .gpg/.asc file, then run gpg --import on that.