Professor Ronald L. Rivest is a well known cryptographer. He was one of the inventors of the RSA algorithm. The 'R' in RSA stands for Rivest. He is also the inventor of the symmetric key encryption algorithms RC2, RC4, RC5, and co-inventor of RC6. The 'RC' stands for Rivest Cipher, alternately Ron's Code. He also authored the MD4 and MD5 hash algorithms.
He is currently professor of Computer Science at MIT. Professor Rivest is the Andrew and Erna Viterbi Professor of Electrical Engineering and Computer Science in MIT's Department of Electrical Engineering and Computer Science. He is a member of MIT's Laboratory for Computer Science, a member of the lab's Theory of Computation Group and a founder of its Cryptography and Information Security Group. He is also a founder of RSA Data Security (now merged with Security Dynamics to form RSA Security) and of Peppercoin.