Challenge 4: Rivest's Beer Bottle Cipher

See http://theory.lcs.mit.edu/~rivest/beer.txt for a description of Ron Rivest's Beer Bottle Cipher.

The challenges are to:

• [50 points] Describe the decryption procedure, and prove it works.
• [100 points or more] Analyze the security of the Beer Bottle Cipher.
• [-50 (be careful on this one!) to +50 points] Develop a new cipher based on "Rugby Road"

Please pay careful attention to this sentence in the Cipher description: The procedure is complicated enough that you probably should not be drinking beer when you try to do it.

University of Virginia Department of Computer Science CS 588: Cryptology - Principles and Applications

David Evans evans@virginia.edu