In group theory, the Pohlig–Hellman algorithm, sometimes credited as the Silver–Pohlig–Hellman algorithm, is a special-purpose algorithm for computing discrete logarithms in a finite abelian group whose order is a smooth integer.
The cipher builds upon the number theory algorithm. Originally proposed in 1976 (about the same time as Diffie-Hellman) and it was not published until after RSA and Diffie-Hellman.
Its multiple encryptions are equal to single encryption.
