84 Chapter 5
without a qualm because you can trust that he is who he says he
is. You cannot trust him with your wallet or your pets, but you
can trust his identity, and that’s all that OpenPGP cares about.
To sign someone’s key, the key owner must provide the
prospective signer with the following:
• Her public key fingerprint, keyid, and user ID (UID)
delivered via anything but the Internet
• Her public key (on a keyserver, web page, floppy disk, or
similar source)
• Her email address
• Her full name
• Proof of her identity
Each key has a unique fingerprint and a keyid that is
unique when combined with the UID. Both GnuPG and PGP
will show you the fingerprint and keyid if you ask (you’ll see
how exactly in the following chapters). For instance, ...