Ronald L. Rivest

Timeline

1. 1969–1974

   Yale and a Stanford PhD

   He earns a bachelor's degree in mathematics at Yale in 1969 and a computer science PhD at Stanford in 1974, supervised by Robert Floyd. At Stanford he briefly works in artificial intelligence, and soon finds his main interest in mathematics and theoretical computer science.

2. 1974–1983

   Joining MIT and inventing RSA

   He joins the MIT faculty in electrical engineering and computer science in 1974. In 1977, with colleagues Adi Shamir and Leonard Adleman, he devises the RSA public-key cryptosystem, and the three found RSA Data Security in 1983.

3. 1976

   Optimal decision trees are NP-complete

   In 1976, he and Laurent Hyafil publish "Constructing optimal binary decision trees is NP-complete" in Information Processing Letters. The paper shows that finding a decision tree that identifies objects through binary-valued questions and minimizes the expected number of questions is NP-complete.

4. 1987–1992

   Decision lists and neural networks

   His 1987 paper "Learning Decision Lists", published in Machine Learning, introduces decision lists and shows that they are efficiently learnable from examples. In 1992, he and Avrim Blum show that training a 3-node neural network is NP-complete. He has worked extensively in machine learning.

5. 1990

   The Introduction to Algorithms textbook

   In 1990, he coauthors the first edition of Introduction to Algorithms with Thomas Cormen and Charles Leiserson, and Clifford Stein joins the authors in later editions. The textbook has sold over 1,000,000 copies and has been translated into 14 languages.

6. 2002–2007

   Turing Award and Marconi Prize

   In 2002, he shares the ACM Turing Award with Adi Shamir and Leonard Adleman for making public-key cryptography useful in practice. In 2007, he is named a Marconi Fellow and prize-winner for his work in cryptography, computer and network security.

7. 2004–2009

   Election security and ThreeBallot

   From 2004 to 2009, he serves on the Technical Guidelines Development Committee, which advises the Election Assistance Commission on voting system certification standards, and chairs its Computer Security and Transparency Subcommittee. In 2006, he invents ThreeBallot, a paper-ballot end-to-end auditable voting system.

8. As of October 2026

   Institute Professor at MIT

   In June 2015, MIT names him an Institute Professor, its highest faculty honor. He is a member of CSAIL's Theory of Computation Group and a founder of its Cryptography and Information Security Group, with research interests in cryptography, computer and network security, algorithms, voting security, climate change and exposure notification. In August 2025, he gives the talk "Evidence-Based Elections and Software Independence" at the DEFCON Voting Village.