Schnorr Identification Protocol

Related Concepts

Authentication; Entity Authentication; Identification

Definition

The Schnorr Identification Protocol is a public-key based challenge-response identification protocol.

Background

The Schnorr Identification Protocol was introduced after, and is comparable to, the identification protocol of Fiat and Shamir and that of Guillou-Quisquater. Schnorr’s protocol relies upon the security of the Discrete Logarithm Problem.

Theory

Schnorr’s protocol is quite simple to describe, and makes novel use of two submitted messages in order to reduce computational complexity. The first message, called a witness, does not depend on either a secret value or a challenge value. The second message, more typically a response in a challenge-response identificationprotocol, is a function of both a secret value and a challenge value, but also of the original witness. The witness can be pre-computed and stored, reducing the computational complexity that might otherwise be required at the time of...