## Professor Andre Scedrov

Office: Room 4E6 in David Rittenhouse Laboratory
Telephone: eight five nine eight three ( Math. Dept. Office: eight eight one seven eight )
Fax: three four zero six three
E-mail: lastname at math
Office Hours: By appointment

"What is to distinguish a digital dollar when it is as easily reproducible as the spoken word? How do we converse privately when every syllable is bounced off a satellite and smeared over an entire continent? How should a bank know that it really is Bill Gates requesting from his laptop in Fiji a transfer of \$100,000,.....,000 to another bank? Fortunately, the mathematics of cryptography can help. Cryptography provides techniques for keeping information secret, for determining that information has not been tampered with, and for determing who authored pieces of information." (From the Foreword by R. Rivest to the "Handbook of Applied Cryptography" by Menezes, van Oorschot, and Vanstone.)

This course for graduate students and advanced undergraduates will discuss security protocol design and analysis and the related areas of cryptography.

## Textbook

• "Cryptography: Theory and Practice. Third Edition" by Stinson. Chapman & Hall/CRC, 2005. ISBN: 1584885084.

## Homework #1 Due in Class on Monday, October 2

• Exercise 1.5 on p. 39 of Stinson.
• Exercise 1.16ab on p. 40 of Stinson.
• Exercise 1.18 on p. 40 of Stinson.
• Exercise 1.26 on p. 43 of Stinson.
• Exercise 1.29ab on p. 44 of Stinson.
• Exercise 2.2 on p. 70 of Stinson.
• Prove that the Caesar cipher does not have perfect secrecy.
This is the complete set of problems for Homework #1 due in class on Monday, October 2.

## Take-Home Midterm Due in Class on Wednesday, November 8

• Prove that if (2^n) - 1 is a prime, then n is a prime, and if (2^n) + 1 is a prime, then n is a power of 2. The first type of prime is called a Mersenne prime, and the second type is called a Fermat prime.
• Using the Fundamental Theorem of Arithmetic, prove that the product of (1 - 1/p) over all primes p is zero.
• Exercise 5.3c on p. 226 of Stinson.
• Exercise 5.7 on p. 226 of Stinson.
• Exercise 5.8 on p. 226 of Stinson.
• Exercise 5.10 on p. 226 of Stinson.
• Exercise 5.12 on p. 227 of Stinson.
• Exercise 5.13 on p. 227 of Stinson.
• Exercise 5.14 on p. 228 of Stinson.
• Exercise 5.15ab on pp. 228-229 of Stinson.
• Exercise 5.16ab on pp. 229-230 of Stinson.
• Exercise 5.20 on p. 230 of Stinson.
This is the complete set of problems for take-home midterm due in class on Wednesday, November 8.

## Take-Home Final Exam Due in DRL 4E6 on Wednesday, December 20 at 10 a.m.

• Exercise 4.6 on p. 157 of Stinson.
• Exercise 4.9ab on p. 157 of Stinson.
• Exercise 4.10 on pp. 157-158 of Stinson.
• Exercise 5.25 on p. 231 of Stinson.
• Exercise 5.32 on p. 232 of Stinson.
• Exercise 6.12 on pp. 277-278 of Stinson.
This is the complete set of problems for take-home final exam due in DRL 4E6 on Wednesday, December 20 at 10 a.m.