How to export public key in PEM format with GnuPG

gnupgopensslpublic-key

I'm writing SW that uses opessl library for verifying DSA signatures. I have public keys from senders in gpg format. How can I convert those into .pem so that openssl can read them?

I found this from another thread:

gpgsm -o secret-key.p12 --export-secret-key-p12 0xXXXXXXXX

To do the export I need to have the keys in gpgsm keyring don't I? I just can't figure out how to import my keys into the keyring gpgsm is using. I end up with errors:

gpgsm --import public.asc
gpgsm: total number processed: 0
gpgsm: error importing certificate: End of file

Can gpgsm somehow use gpg:s keyring and do the export from there?

Best Answer

Your export command is correct but as you suppose, the gpgsm's keyring is empty. You can check that with:

gpgsm --list-keys

The output will be nothing.

For your last question: Nope. gpg and gpgsm use different databases. More info is here. You have to create or obtain an OpenSSL key/cert pair and import it (in PKCS#12 format) into gpgsm keyring (usually ~/.gnupg/pubring.kbx) so the import command must be:

gpgsm --import mycert.p12

You can export the keys from one system, convert them and import to another one, but the so-called conversion just supplies the metainfo (in most cases) and a brand new cert/key is being created with that metainfo. You can look here for conversion examples.

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