Ron Rivest, Adi Shamir, and Leonard Adleman

Ron Rivest, Adi Shamir, and Leonard Adleman are the three MIT-affiliated computer scientists who, working together in 1977, devised the RSA public-key cryptosystem — one of the first practical schemes allowing secure encryption and digital signatures without the sender and receiver first sharing a secret key. The trio is almost always discussed jointly because their contribution was a single, collaborative invention: one algorithm, one landmark paper, one patent, and one shared Turing Award.

Backgrounds

Ronald L. Rivest was born May 6, 1947, in Schenectady, New York. He earned a bachelor's degree in mathematics from Yale University (1969) and a Ph.D. in computer science from Stanford University (1974), and became a professor at MIT, where he remains an Institute Professor in the Department of Electrical Engineering and Computer Science and the Computer Science and Artificial Intelligence Laboratory (CSAIL).

Adi Shamir was born July 6, 1952, in Tel Aviv, Israel. He earned a B.Sc. in mathematics from Tel Aviv University (1973) and an M.Sc. and Ph.D. in computer science from the Weizmann Institute of Science (1975, 1977). After postdoctoral research that brought him to MIT (1977-1980), he joined the Weizmann Institute faculty in 1980, where he remained a professor.

Leonard Max Adleman was born December 31, 1945, in San Francisco, California. He earned a B.A. in mathematics (1968) and a Ph.D. in electrical engineering and computer science (1976), both from UC Berkeley, studying under Manuel Blum. Adleman became a professor at the University of Southern California.

Inventing RSA

At MIT in 1977, the three researchers set out to find a practical implementation of the public-key cryptography concept that Whitfield Diffie and Martin Hellman had proposed the year before. According to accounts of the discovery, Rivest formulated the key mathematical idea, based on the difficulty of factoring large numbers, after a night of work in April 1977. The scheme was first publicized in Martin Gardner's "Mathematical Games" column in Scientific American in August 1977, and the formal academic description, "A Method for Obtaining Digital Signatures and Public-Key Cryptosystems," was published in Communications of the ACM in February 1978. The algorithm's name, RSA, is formed from the authors' surnames. A patent application was filed in December 1977, and U.S. Patent 4,405,829 was granted on September 20, 1983.

It was later revealed that an equivalent method had been described in a classified 1973 internal document by British mathematician Clifford Cocks at GCHQ; that work was never deployed and remained secret until declassified in 1997, so it did not influence the MIT group's independent discovery.

Company, Turing Award, and Legacy

In 1982, Rivest, Shamir, and Adleman co-founded RSA Data Security to commercialize the algorithm; the company was acquired by Security Dynamics in July 1996, after which the combined firm was renamed RSA Security. The RSA patent expired in September 2000, and RSA Security released the algorithm to the public domain shortly beforehand, on September 6, 2000.

In 2002, the Association for Computing Machinery awarded Rivest, Shamir, and Adleman the ACM A.M. Turing Award — computing's highest honor — "for their ingenious contribution for making public-key cryptography useful in practice." RSA underlies much of modern secure communication, including HTTPS/TLS, digital signatures, and secure email. Each recipient also has an independent body of work: Rivest co-designed the MD5 hash function and RC4/RC5 ciphers and researches secure voting; Shamir co-invented differential cryptanalysis, the Shamir secret-sharing scheme, and the Feige-Fiat-Shamir identification scheme; and Adleman pioneered DNA computing in 1994 and is credited with coining the term "computer virus."

Timeline

• 1945-12-31Leonard Adleman is born in San Francisco, California.
• 1947-05-06Ron Rivest is born in Schenectady, New York.
• 1952-07-06Adi Shamir is born in Tel Aviv, Israel.
• 1977Rivest, Shamir, and Adleman devise the RSA public-key cryptosystem at MIT.
• 1977-08The RSA scheme is publicized in Martin Gardner's 'Mathematical Games' column in Scientific American.
• 1977-12Patent application for the RSA algorithm is filed.
• 1978-02'A Method for Obtaining Digital Signatures and Public-Key Cryptosystems' is published in Communications of the ACM.
• 1982Rivest, Shamir, and Adleman co-found RSA Data Security.
• 1983-09-20U.S. Patent 4,405,829 for the RSA algorithm is granted.
• 1994Adleman demonstrates DNA computing, solving a computational problem using DNA molecules.
• 1996-07Security Dynamics acquires RSA Data Security, later renaming the combined company RSA Security.
• 2000-09-06RSA Security releases the RSA algorithm into the public domain ahead of patent expiration.
• 2002Rivest, Shamir, and Adleman receive the ACM A.M. Turing Award.