In 1977 MIT Professors Rivest, Shamir and Adleman discovered the RSA encryption algorithm, which is the basis for most public-key encryption used on the Internet today (including the SSL implementation in your web browser.)
Last year they were awarded the highest honor in computer science for this discovery, the ACM Turing Award.
The acceptance speech lecture is now available online. You need Quicktime, Shockwave, or WMA to listen. You can even get all of the slides! Enjoy!