Ronald Linn Rivest (/rɪˈvɛst/;[3][4] born May 6, 1947) is an American cryptographer and computer scientist whose work has spanned the fields of algorithms and combinatorics, cryptography, machine learning, and election integrity.

His former doctoral students include Avrim Blum, Benny Chor, Sally Goldman, Burt Kaliski, Anna Lysyanskaya, Ron Pinter, Robert Schapire, Alan Sherman,[1] and Mona Singh.

He has also made significant contributions to algorithm design, to the computational complexity of machine learning, and to election security.

[C7] He designed the MD4 and MD5 cryptographic hash functions, published in 1990 and 1992 respectively,[C4][C5] and a sequence of symmetric key block ciphers that include RC2, RC4, RC5, and RC6.

[C6][C8] Other contributions of Rivest to cryptography include chaffing and winnowing, the interlock protocol for authenticating anonymous key-exchange, cryptographic time capsules such as LCS35 based on anticipated improvements to computation speed through Moore's law, key whitening and its application through the xor–encrypt–xor key mode in extending the Data Encryption Standard to DES-X, and the Peppercoin system for cryptographic micropayments.

[A2][12] Rivest's 1974 doctoral dissertation concerned the use of hash tables to quickly match partial words in documents; he later published this work as a journal paper.

[A3] His research from this time on self-organizing lists[A4] became one of the important precursors to the development of competitive analysis for online algorithms.

[13] In the early 1980s, he also published well-cited research on two-dimensional bin packing problems,[A5] and on channel routing in VLSI design.