paperkey 1.6 Backup OpenPGP keys to paper

Paperkey extracts the secret bytes from an OpenPGP (GnuPG, PGP, etc) key for printing with paper and ink, which have amazingly long retention qualities. To reconstruct a secret key, you re-enter those bytes (whether by hand, OCR, QR code, or the like) and paperkey can use them to transform your existing public key into a secret key.