# Class 18 - Notes

### Upcoming Schedule

Project 4 is due Wednesday, 16 March. If you haven't made progress on it yet, you should be working on it over spring break.

The first chance to pass the Blue Belt test will be Monday, 21 March. (More details on this will be given in the first class after Spring Break).

### Slides

# Merkle's Puzzles

**Protocol:**

*N* is the number of puzzles.

*w* is the amount of work to solve each puzzle.

How much work does the legitimate receiver need to do?

How much work does the eavesdropper need to do?

## Links

Ralph Merkle's history of public-key cryptography, including his (rejected) undergraduate course proposal, and rejection letter (that is actually quite savvy, talking about the work advantage being too little).

Applied Cryptography section on Merkle's Puzzles (this is a direct link to the videos, or you can watch them with the interactive quizzes in the Udacity player

*Cryptography Pioneers Win Turing Award*, New York Times, 1 March 2016.

Turing Award Announcement, 29 February 2016.