In public key encryption systems everybody has a pair of keys, public and private:
For digital signatures the same keys are used, but the other way around:
Private key is kept in secrecy by its owner;
Public key is disseminated as widely as possible.
A fingerprint is a short digest of a public key, designed to simplify verifying public keys over the phone (public keys themselves are too long to dictate).
A fingerprint of a public key is quite alike a fingerprint of a person: there exist no two public keys with coinciding fingerprints. Accordingly, if the fingerprints match, the keys themselves will match. There is no way for an impostor to invent a public key that would have the same fingerprints as the fingerprints of our public key posted on this page.
Printed matter. You may see our public key's fingerprints on some of our stationary, business cards, in catalogs, and some other printed materials.