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A Public Key Cryptosystem and a Signature Scheme Based on Discrete Logarithms (ElGamal 1985)

Last modified: 2026-10-27

DOI: 10.1109/tit.1985.1057074 · URL: https://doi.org/10.1109/TIT.1985.1057074

Summary

Introduces ElGamal encryption and the ElGamal signature scheme, both based on discrete logarithms. ElGamal encryption is homomorphic and re-randomizable, which makes it a standard building block in ZKP protocols (verifiable encryption, escrowed identity, mix-nets), and the signature scheme is the ancestor of Schnorr signatures and DSA/ECDSA. (IEEE Transactions on Information Theory 1985.)

Related resources

• Efficient Signature Generation by Smart Cards (Schnorr 1991) (paper, 1991)
• New Directions in Cryptography (Diffie, Hellman 1976) (paper, 1976)