| # | Date | Topics | Handouts | Reading | Homework | |
|---|---|---|---|---|---|---|
| 1 | F 9/7 | Introduction | - | Singh Ch 1, Barr p. 1-4 | - | |
| 2 | M 9/10 | Shift ciphers, arithmetic mod 26 | Letters <-> numbers | This is in Barr 2.1 | HW 1: Barr p. 66: 1 (due 9/12) | |
| 3 | W 9/12 | Modular arithmetic: addition (table), subtraction, multiplication (table), inverses, decoding shift ciphers | Letter frequencies, bar graph | In Barr 2.1 | - | |
| 4 | F 9/14 | Number line, smallest remainder (find using long division or a calculator), find multiplicative inverses (look in multiplication table) | Mystery cipher #1 (due 10am F 9/21) | In Barr 2.1 | HW 2: Barr p. 80: 1 (due 9/17) | |
| 5 | M 9/17 | Multiplicative ciphers ("decimation" ciphers) | - | Barr 2.2 | HW 3: Barr p. 66: 4, 6; p. 80: 2, 3 (due 9/19) | |
| 6 | W 9/19 | Affine ciphers | - | Barr 2.2 | - | |
| 7 | F 9/21 | Transposition ciphers | - | Barr 2.4 | HW 4: p. 80: 4, 5, 7. p. 105: 1, 2, 5 (due 9/26) | |
| 8 | M 9/24 | Substitution ciphers. This is the most well known cipher system, but it's not really mathematical, so we won't spend much time on it. | "ETNAN ..." and "YIFQF..." | Barr 2.3 | HW 5: Please finish "ETNAN..." (due 9/28). Do some work on "YIFQF..."; it's not necessary to finish it. (due 10/1) | |
| 9 | W 9/26 | Vigenere ciphers: encipher, decipher | Vigenere square; "AWY..." (Vigenere CT with three letter keyword) | Barr 2.5, Singh p. 48-51, 67-78 | - | |
| 10 | Fri 9/28 | Vigenere cipher: cyptanalysis: find keyword given its length | second mystery cipher | Barr p. 111-115 | HW 6: p. 118: 1a, 2a, 3a, 6 (don't forget to explain your answer for this problem). Due 10/3 | |
| 11 | M 10/1 | Vigenere cipher: cryptanalysis: find the length of the keyword using the Kasiski test | "JSQIJ..." | Barr: p. 139-140; Singh p. 69-72, 78 | HW 7: p. 141: 8 (due 10/5) | |
| 12 | W 10/3 | Permutations and combinations | - | Barr 2.6 | - | |
| 13 | F 10/5 | Probability | - | Barr 2.6. Additional reading: Barr p. 5-17, Singh ch. 2 | HW 8: p. 130: 1ab, 2ab, 3, 4, 5a, 6a (due 10/12) | |
| 14 | W 10/10 | Friedman's index of coincidence | - | Barr 2.7 | - | |
| 15 | F 10/12 | Quiz 1 (on shift ciphers; like the homework p. 66, including #11) | - | - | HW 9: p. 141: 1ab, 2, 3 (it's better to do this one with someone else, though both of you should hand it in), 4 (due 10/17) | |
| 16 | M 10/15 | Vigenere autokey cipher | - | Kahn p. 147; Wikipedia "autokey cipher" | - | |
| - | - | Playfair cipher (Note that there are different ways of doing it (cf. eg Barr and Singh) | - | Barr p. 16; Singh p. 372; Kahn p. 198-202 | - | |
| 17 | W 10/17 | Binary arithmetic | - | Barr 3.1 (p. 178-179) | - | |
| 18 | F 10/19 | Quiz 2 (on affine ciphers; like the homework p. 80) | - | - | - | |
| - | - | Binary arithmetic (addition mod 2); binary Vigenere, LFSR | ASCII table (better: see Wikipedia entry for "ASCII") | Barr section 3.4, Singh p. 245-247 | - | |
| 19 | Mon 10/22 | Counting in binary; Introduction to LFSR | - | Barr 3.4 | - | |
| 20 | Weds 10/24 | Quiz 3 (on transposition and Vigenere ciphers) | - | - | - | |
| - | - | LFSR (con't): Vigenere using ASCII; maximal length key | - | full ASCII table | HW 10: p. 185 (binary): 1ab, 4, 5. p. 36 (Playfair): 16, 17. p. 219 (LFSR): 1, 2, 3ab. (due 10/30) | |
| 21 | Fri 10/26 | LFSR (con't) | - | - | - | |
| - | - | Alberti cipher disk | - | Barr p. 7-9; Kahn p. 125-130 | HW 11: p. 34: 7, 8 (due 10/31) | |
| 22 | Mon 10/29 | Introduction to the Enigma | You can find an Enigma simulator here. Click on the link on the left side of the page. It needs to be downloaded. | Singh Ch. 3; the mechanism is described p. 127-142. Barr p. 23-25 | - | |
| 23 | Weds 10/31 | The Enigma (con't): parts (rotors, rings, reflector, plugboard), setup | Page from a German codebook | - | - | |
| 24 | Fri 11/2 | Test 1. Information, practice problems | - | - | - | |
| 25 | Mon 11/5 | The Enigma (con't): number of possible settings; use of the machine (doubled message indicators; cracking the Enigma (Polish effort, Bletchley Park | - | Singh Ch. 4 | - | |
| 26 | Weds 11/7 | Introduction to public key ciphers (discrete log, RSA, knapsack). | - | Barr p. 26-28 | - | |
| - | - | Knapsack ciphers | - | Barr 4.2 | HW 12: p. 272: 1abc, 2, 3 (due 11/12) | |
| 27 | Fri 11/9 | Knapsack ciphers: theory | - | - | - | |
| 28 | Mon 11/12 | Knapsack ciphers: demonstration | The knapsack cipher | - | HW13: p. 272: 4 (here 91^(-1) mod 8017 is 881), 5 (here 5^(-1) mod 1009 is 202), 7, 9 (here 6^(-1) mod 4091 is 682) (due 11/16) | |
| 29 | Weds 11/14 | Prime numbers: properties | Copy of table of primes in Barr p. 370 (use for problems 2 and 4) | Barr 4.1 | HW 14: Barr p. 260 (4.1): 1,2,4,5,6ab (due 11/19) | |
| 30 | Fri 11/16 | Introduction to the RSA cipher | - | Barr 4.4 | - | |
| - | - | - | Reading: A cryptologist in Iraq | Singh Ch 5, 6. | - | |
| 31 | Mon 11/19 | Polybius checkerboard | - | Barr p. 5; Kahn p. 83 | - | |
| - | - | ADFGVX cipher | - | Barr p. 21; Singh p. 374; Kahn p. 339-350 | HW 15: Barr p. 36: 20, 21 (due 11/28) | |
| - | - | Test1A (optional, but must be taken by 11/28.) | Anyone can take this test. It is 50 minutes and closed book; download it when you're ready to take it. You may use a calculator. | - | - | |
| - | - | - | - | - | Mystery cipher 3: Cryptograms in foreign languages. Use Letter frequencies in foreign languages. (due 11/28) | |
| 32 | Mon 11/26 | The discrete logarithm problem | - | Barr p. 297-299 | - | |
| - | - | The key exchange problem; padlocked box | - | Singh p. 256-260 | - | |
| 33 | Wed 11/28 | Diffie-Hellman key exchange | - | Barr p. 299-301; Singh p. 260-267 | - | |
| - | - | Digital signatures using RSA | - | Barr 4.6 p. 307; Schneier p. 473 | - | |
| - | - | Test II (take home, due 12/10) | Test II: Answers | - | - | |
| 34 | Fri 11/30 | digital signatures (con't); hashing | - | Barr 3.6 | - | |
| 35 | Mon 12/3 | hashing (con't) | - | - | HW 16 (due 12/10): RSA exercises and Enigma exercises | |
| 36 | Weds 12/5 | PGP (guest speaker Ron Peterson) | - | Singh Ch. 7 | HW 17: Barr p. 241 (3.6): 1, 2; also key exchange, and digital signatures. (due 12/12) | |
| 37 | Fri 12/7 | "Spies" (video on codebreaking. It will be on reserve at the library.) | - | Reading: Sharing the Burden: Women in Cyrptology during WWII (find this title on the NSA page) | - | |
| 38 | Mon 12/10 | The M209B. Guest speaker: Professor Emeritus Curtis Smith. You will get a chance to use these small WWII coding machines. | You can find a simulator here. | - | - | - |
| 39 | Weds 12/12 | Final exam | - | - | - | |
| - | - | DES | An online DES | Barr 5.1. (Also the wikipedia entry is pretty good.) | - | |
| - | - | AES (Rijndael) | An online Rijndael, a visualization of how it works, and an animation of this process. | The wikipedia entry is pretty good. (This is so new that there's nothing in our texts.) | All homework is due on Weds 12/12 at 11:59 pm. |
Here are some useful websites. Use with care--their accuracy can't be guaranteed.