| Problem number | Problem | Due date |
|---|---|---|
| 1 | Complete the solution. | T 1/6 |
| 2 | Problems 1-3, Cryptograms and Spygrams, p.3
Hint: -4 <deciphering shift <7 (-7 <enciphering shift <4). | T 1/6 |
| 3 | Quote 100 consecutive letters of random text
and tally the individual letter frequencies. | T 1/6 |
| 4 | Make a table showing the multiplicative inverses (reciprocals) modulo 26 of the numbers 1, 2, 3, 4, ... , 25, 26. (Some do not exist.) Keep a copy for your reference. | M 1/12 |
| 5 | Find all the solutions of
(a) 20 x = 4 (mod 30) (b) 20 x = 10 (mod 30). | M 1/12 |
| 6 | Handout: "Modular Arithmetic and Affine Ciphers" | M 1/12 |
| 7 | Barr 1.1: #1-6, 9-11, 14 | M 1/12 |
| 8 | Barr 1.1: #7-8, 12-13, 15-24 (as many as you can get) | T 1/13 |
| X | Extra credit: Determine number of monoalphabets that change every letter. | |
| 9 | Little Orphan Annie crypt (handout) | R 1/15 |
| 10 | The Gold-Bug crypt (handout) | M 1/19 |
| 11 | Matrix inverse mod 26: (ps) (pdf) ( html) | R 1/22 |
| 12 | In-class: Lewand sect. 3.3 #1, 2 | R 1/22 |
| X | Extra credit: Solve one or more of the Exam 3
cryptograms:
| F 1/30 |
| 13 | Solve the columnar transpostion cipher IPLAI HLTCH EFAOH ORWKR ACTIT AMLNO NPTRO DCEMO RTTBE LEXAR SABDI AEMSN PWOAS LUNOE EHR. It contains the words "the probable." (The solution was begun in class 1/27.) | W 1/28 |
| 14 | Let g = gcd(345, 543).
| W 1/28 |
| X | Extra credit: Solve Lewand 4.3#3. (Turn in your computer output.) | F 1/30 |
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