Digital Signatures: Background and Definitions

Abstract

Loosely speaking, a digital signature scheme offers a cryptographic analogue of handwritten signatures that, in fact, provides much stronger security guarantees. Digital signatures serve as a powerful tool and are now accepted as legally binding in many countries; they can be used for certifying contracts or notarizing documents, for authentication of individuals or corporations, and as components of more complex protocols. Digital signatures also enable the secure distribution and transmission of public keys and thus, in a very real sense, serve as the foundation for all of public-key cryptography.