Adi Shamir

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Lore & Background

Adi Shamir is an Israeli cryptographer and inventor, born in Tel Aviv on July 6, 1952. He earned a bachelor’s degree in mathematics from Tel Aviv University in 1973, followed by a master’s and doctorate in computer science from the Weizmann Institute in 1975 and 1977. After a postdoctoral year at the University of Warwick and research at the Massachusetts Institute of Technology from 1977 to 1980, he returned to Israel to join the Weizmann Institute’s faculty of Mathematics and Computer Science. Since 2006, he has also been an invited professor at the École Normale Supérieure in Paris. Shamir is best known as a co-inventor of the Rivest–Shamir–Adleman (RSA) algorithm, for which he, along with Ron Rivest and Len Adleman, received the 2002 ACM Turing Award. He also co-invented the Feige–Fiat–Shamir identification scheme and, with Eli Biham, discovered differential cryptanalysis, a general method for attacking block ciphers. His other contributions include the Shamir secret sharing scheme, visual cryptography, the TWIRL and TWINKLE factoring devices, and the breaking of the Merkle-Hellman knapsack cryptosystem. He introduced identity-based cryptography in 1984 and, with Amos Fiat, devised the Fiat–Shamir heuristic. Shamir co-founded RSA Security and has developed side-channel attacks, including acoustic cryptanalysis to extract RSA keys from a laptop’s sound. Since the late 2010s, he has studied the security of machine learning systems. Beyond cryptography, he found the first linear time algorithm for 2-satisfiability and helped prove the equality of the complexity classes PSPACE and IP.

Reader's Guide

Adi Shamir’s significance stems from his foundational role in modern cryptography, most notably as co-inventor of the RSA algorithm, one of the first practical public-key cryptosystems, which became essential for secure internet communications. He also introduced identity-based cryptography, allowing a user’s public key to be derived from a unique identifier like an email address, and co-developed the Fiat–Shamir heuristic, a method that converts interactive identification protocols into digital signature schemes. Beyond these, Shamir invented the Shamir secret sharing scheme, visual cryptography, and, with Eli Biham, discovered differential cryptanalysis, a general method for attacking block ciphers that was later revealed to have been previously known but kept secret by IBM and the NSA. He co-founded RSA Security, the company behind the annual RSA Conference. His cryptanalytic work includes breaking the Merkle-Hellman knapsack cryptosystem, real-time attacks on the A5/1 cipher used for GSM mobile encryption, and the Fluhrer–Mantin–Shamir attack on the RC4 cipher that exposed weaknesses in the WEP Wi-Fi security protocol. He also developed side-channel attacks, including extracting RSA keys from a laptop’s acoustic emissions during decryption. In computer science, he found the first linear-time algorithm for 2-satisfiability and helped prove the equality of the complexity classes PSPACE and IP. Later work includes studying adversarial examples in machine learning and extracting neural network parameters. His contributions earned the ACM Turing Award in 2002, the Israel Prize, the Japan Prize, and the Wolf Prize in Mathematics.

Did You Know?

• Adi Shamir is a Turing Award recipient, recognized for his foundational contributions to cryptography.
• He co-invented the RSA algorithm, a foundational technology in modern cryptography.
• Together with Eli Biham, he discovered differential cryptanalysis in the late 1980s, a general method for attacking block ciphers.