The public key is the primary key (the ID) of a key. Other fields are:

• Private key (for secret key ring) — the private key may be protected by a pass phrase and a pass file
• Nickname (for humans)
• Full name (for humans)
• Creation and expiration dates

Signatures

Keys may be signed, we treat key signatures as separate entities. A signature consists of

• The pubkey of the signed key
• The pubkey of the signer
• The “digest”, the cryptographic checksum that proves that the signer has signed the key

This feature will be implemented when Dan Bernstein integrates signatures into NaCl; maybe a bit earlier, since the code for these signatures is already tested.