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In cryptography, the Pointcheval-Stern signature algorithm is a digital signature scheme based on the closely related ElGamal signature scheme. It changes the ElGamal scheme slightly to produce an algorithm which has been proven secure in a strong sense against adaptive chosen-message attacks. That is, if the discrete logarithm problem is intractable in a strong sense.[1][2]

David Pointcheval and Jacques Stern developed the forking lemma technique in constructing their proof for this algorithm. It has been used in other security investigations of various cryptographic algorithms.



  1. D Pointcheval and J Stern. Security proofs for signature schemes. in U Maurer, ed. Adv in Crypt -- Eurocrypt '96, 387-398, Springer-Verlag, 1996. Lect Notes in Comp Sci, nr 1070
  2. D Pointcheval and J Stern, Security arguments for digital signatures and blind signatures, J Crypt 13(3):361-396, 2000.