Many of Fiat's most highly cited publications concern cryptography, including his work with Adi Shamir on digital signatures (leading to the Fiat–Shamir heuristic for turning interactive identification protocols into signature schemes)[3] and his work with David Chaum and Moni Naor on electronic money, used as the basis for the ecash system.
[4] With Shamir and Uriel Feige in 1988, Fiat invented the Feige–Fiat–Shamir identification scheme, a method for using public-key cryptography to provide challenge–response authentication.
[5] Along with Benny Chor, Moni Naor and Benny Pinkas, he made a contribution to the development of Traitor tracing, a copyright infringement detection system which works by tracing the source of leaked files rather than by direct copy protection.
[6] With Gerhard Woeginger, Fiat organized a series of Dagstuhl workshops on competitive analysis of online algorithms, and together with Woeginger he edited the book Online Algorithms: The State of the Art (Lecture Notes in Computer Science 1442, Springer-Verlag, 1998).
[11] He has taken inspiration from the game Tetris in developing new job shop scheduling algorithms,[12] as well as applying competitive analysis to the design of game-theoretic auctions.