The document to encrypt should be mounted into the /tmp/encrypt directory of the container. The resulting .gpg file to share with veracode will appear next to it once the container terminates.
docker run --rm -it -v "${PWD}/encrypt/:/tmp/encrypt/" captainkark/veracode-gpg /tmp/encrypt/foobar.txt
Afterwards, on the host machine:
$: ls -A1 encrypt/
foobar.txt
foobar.txt.gpg
You can attach foobar.txt.gpg to an email (or whatever) to communicate secrets with veracode.
The public key that comes baked into the image can be verified, if desired.
$: docker run --rm -it --entrypoint gpg captainkark/veracode-gpg --list-keys
Which should output the following:
/root/.gnupg/pubring.kbx
------------------------
pub rsa2048 2012-04-24 [SC]
58F651DCBE9A644A8C01A485A56B91234E651127
uid [ unknown] Veracode MPT Team ⟨mpt@veracode.com⟩
sub rsa2048 2012-04-24 [E]