Insecure primitive elements in an ElGamal signature protocol. (4th May 2015)

• Record Type: Journal Article
• Authors: Khadir, Omar
• Is Part Of: Journal of discrete mathematical sciences & cryptography. Volume 18:Number 3(2015)
• Page Start: 237
• Page End: 245
• Publication Date: 2015-05-04
• Subjects: ElGamal signature scheme -- public key cryptography -- cryptanalysis; 94A60; Computer science -- Mathematics -- Periodicals; Cryptography -- Periodicals; Computer science -- Mathematics; Cryptography; Periodicals; 004.0151
• DOI: 10.1080/09720529.2014.927648
• Languages: English
• ISSNs: 0972-0529

Abstract

Abstract: Consider the classical ElGamal digital signature scheme based on the modular relation α m ≡ y r r s [ p ]. In this work, we prove that if we can compute a natural integer i such that α i mod p is smooth and divides p − 1, then it is possible to sign any given document without knowing the secret key. Therefore we extend and reinforce Bleichenbacher's attack presented at Eurocrypt'96.