To encrypt a GPG key for use by CircleCI:
openssl aes-256-cbc \
-e \
-md sha1 \
-in ./config/secrets/ci/gpg.private \
-out ./.circleci/gpg.private.enc \
-k "<passphrase>"
To check decryption is working correctly:
openssl aes-256-cbc \
-d \
-md sha1 \
-in ./.circleci/gpg.private.enc \
-k "<passphrase>"