Let a be an integer such that GCD(a, p) = 1. Analysis of ElGamal Digital Signature … It has Before proceeding, we need a result from number theory. ElGamal Signature Example • use field GF(19) q=19 and a=10 • Alice computes her key: – A chooses xA=16 and computes yA=10 ... • a digital signature scheme only • security depends on difficulty of computing discrete logarithms • variant of ElGamal and Schnorr schemes It was described by Taher ElGamal in 1984. integer XA, such that 1 6 XA