An OpenPGP key archiver.
# To take a specific secret key and generate a text file with the secret data:
paperkey --secret-key <path/to/secret_key.gpg> --output <path/to/secret_data.txt>
# To take the secret key data in 'secret_data.txt' and combine it with the public key to reconstruct the secret key:
paperkey --pubring <path/to/public_key.gpg> --secrets <path/to/secret_data.txt> --output <secret_key.gpg>
# To export a specific secret key and generate a text file with the secret data:
gpg --export-secret-key <key> | paperkey --output <path/to/secret_data.txt>