Instructor: Samuel S. Wagstaff, Jr.
Phone: 49-46022; E-mail: ssw@cerias.purdue.edu
Prerequisites: CS 251, CS 381, CS 426 and MA 351.
The real prerequisites for CS 555.
Text: Introduction to Modern Cryptography by J. Katz and Y. Lindell, Chapman and Hall/CRC Press, 2008, ISBN 978-1-58488-551-1. See also the errata here.
Reference: Cryptanlysis of Number Theoretic Ciphers, by Samuel S. Wagstaff, Jr., Chapman and Hall/CRC Press, 2003. ISBN 1-58488-153-4. See also the errata here.
Recommended additional reading: Applied Cryptography (2nd edition), by Bruce Schneier, Wiley, 1996. See also the errata here.
See also here for the new Advanced Encryption Standard algorithm Rijndael.
The overall course policies are the same as Spaf's.
Link to a list of web sources on cryptography and security.
Location and Time: LWSN B134, MWF 9:30-10:20.
Office: LWSN 1167; Office hours: Monday 3:30-4:30 PM, Wednesday 1-2 PM.
Grading: Homework: 20%; Midterm exam 20%; Project 20%; Final exam 40%.
Teaching Assistant: Chenyun Dai, Email: daic@cs.purdue.edu .
Office hours of Teaching Assistant: Monday 1 - 2 PM.
Day-by-day list of topics covered.
Please use a word processor like Latex or MS Word to format your homework solution.
Homework # 1, due Wednesday, February 3, 2010, 9:30 AM, on paper, in class. In question 2, your reasoning is much more important than the numbers you give as the answers. Unsupported guesses are worthless. Text of the questions.
Homework # 2, due Wednesday, February 10, 2010, 9:30 AM, on paper, in class. In question 1, your reasoning is much more important than the numbers you give as the answers. Unsupported guesses are worthless. Text of the questions.
Homework # 3, due Wednesday, February 17, 2010, 9:30 AM, on paper, in class. Text of the questions.
Block, stream ciphers, LFSRs, meet-in-the-middle attacks.
Divisibility, Arithmetic with large integers, GCD.
Congruences: Definition and single linear ones.
Transposition ciphers and substitution ciphers, IC.
Substitution ciphers, product ciphers.
Congruences for fun and profit.
Fermat, Euler, fast exponentiation, finding large primes.
Threshold schemes, Digital Signature Standard and Subliminal Channels.
Examples of the Extended Euclidean Algorithm and the Chinese Remainder Theorem
Large primes via Pocklington-Lehmer.
P-H, RSA, ElGamal, Massey-Omura ciphers, signatures.
ElGamal public-key cryptosystem.
Diffie-Hellman key exchange, discrete logs.
Mental poker and quadratic residues.
Euler's Criterion, Legendre symbol.
Quadratic congruences, Oblivious transfer, Zero-knowledge proofs.
Hash and other one-way functions.
Subliminal channels; the one in DSA.
Homework # 4, due Tuesday, February 17, 2009, 3:00 PM, on paper, in class. Text of the questions.
Homework # 5, due Tuesday, March 24, 2009, 3:00 PM, on paper, in class. Text of the questions.
Homework # 6, due Thursday, April 9, 2009, 3:00 PM, on paper, in class. Text of the questions.
Homework # 7, due Tuesday, April 21, 2009, 3:00 PM, on paper, in class. Text of the questions.
Homework # 8, not due. Just do it for fun and to practice for the final. Text of the questions.
Some old slides you might enjoy.
Information theory: Definition of entropy.
Information theory: Rate, perfect secrecy.
Key equivocation, unicity distance.
Transposition ciphers and substitution ciphers, IC.
Synchronous and self-synchronous stream ciphers, CBC.
Congruences: CSR, XEuclid, multiplicative inverses.
Fermat, Euler, fast exponentiation, finding large primes.
Entropy question and proposed solution.
Substitution ciphers, product ciphers.