See also Security
A method of authentication. The most commonly used form of authentication in the real world is one's own signature, which can be verified by a handwriting expert. Digital Signatures are hashes that are unique to an individual message. Even a slight change (such as an extra space) to a message will alter a digital signature and they are verifyable to a specific Public-Key.
- Prove a user's identity, preventing mail spoofing
- Confirm a file's integrity (based on your reputation) such as for the PuTTY client
- Allows user authentication for network services
Of course, if someone were to get your signature password and possibly your computer, they could conceivably forge your signature. Because of this digital signatures cannot be used to verify real-world identities remotely because one cannot determine if the signature belongs to the person who claims ownership.
Other real-world methods of authentication include:
- Retinal scan
- Fingerprints (usually the thumb)
- DNA sample