A group digital signature technique for authentication

A group digital signature technique using a digital signature algorithm and a challenge-response identification protocol is proposed to provide effective authentication. The proposed digital signature algorithm is based on solving quadratic congruence, factorization, and discrete logarithm problems. Based on the public key infrastructure, group members generate their public-private keys first. The designed authority generates the group member´s identity code (ID), the group identity mark, and the group secret key. Every group member keeps his/her private key and the ID for signing. These parameters can ensure only members who can make signatures and provide data authenticity and nonrepudiation for any signer. The challenge-response identification protocol with overlapping-shifting-EXOR logical operations is proposed to ensure the signer to obtain group secret key securely and prevent any signer from making false claims. According to the security analysis, the processing time of the proposed approach is faster than the existing RSA and ElGamal group digital signature systems. Moreover, the proposed method would be suited to microprocessor-based devices such as smart cards, computer systems, networks and control systems because of its simplicity, confidentiality, and fast processing speed.