The ElGamal encryption scheme Encryption Letm∈ z be a message For k=i(p, g,x,y):y=g modp), and secret random number ke zp-l, define: exm, k)=(S,t), where s=gk modp t- m y modp Decryption For s, te Zp, define dx(s,t)=t(sr)mod p 1212 The ElGamal encryption scheme • Encryption Let m  Zp * be a message. For K = {(p,g,x,y): y = g x modp }, and secret random number k  Zp-1 , define: eK (m,k) = (s,t), where – s = gk modp – t = m y k modp • Decryption For s,t  Zp * , define: dK (s,t) = t(s x ) -1mod p