Understanding Keyoxide

Cryptographic programs

OpenPGP

Here's the Wikipedia page on PGP which has a chapter dedicated to OpenPGP.

In short, OpenPGP is a popular and widely used asymmetric cryptography standard described in the IETF's RFC 4880. OpenPGP key pairs can contain UserIDs and subkeys which can encrypt/decrypt or sign/verify data.

Keyoxide uses OpenPGP for both types of profiles: signature profiles and openpgp profiles.