Digital Signature Standard

Related Concepts

Digital Signature Scheme; ElGamal Digital Signature Scheme; Schnorr Digital Signature

Background

The Digital Signature Standard (DSS), first proposed by Kravitz [2] in 1991, became a US federal standard in May 1994. It is published as Federal Information Processing Letters (FIPS) 186. The signature scheme is based on the ElGamal digital signature scheme and borrows ideas from Schnorr digital signatures for reducing signature size.

Theory

We describe a slight generalization of the algorithm that allows for an arbitrary security parameter, whereas the standard only supports a fixed parameter. The signature scheme makes use of modular arithmetic and works as follows:

Key Generation. Given two security parameters $\tau ,\lambda \in \mathbb{Z}\ (\tau > \lambda )$ as input do the following:

• 1. Generate a random λ-bit prime q.

• 2. Generate a random τ-bit prime p such that q divides p − 1.

• 3. Pick an element $g \in {\mathbb{Z}}_{p}^{{_\ast}}$ of order q.

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