To know: The libraries are scanning chapters of the textbook for me to upload to canvas. But I can only have one or two on there at a time. So if you’d like to read Chapter 2, please access it soon, as it will eventually get taken down. The relevant parts of Chapter 2 for the course right now are: intro, 2.1, 2.2, 2.3, 2.4, 2.6, 2.7, 2.9, 2.12. I’ve done some picking-and-choosing, so what I’ve covered in notes/class/videos/exercises is the official material, not the book. But the book should provide a good backup resource and alternate explanation for lots of what I’ve done.

To know: The assessment for this module will open tomorrow and be due Thursday September 10th. After that there’ll be a chance to correct your errors for some increase in credit. The material covered is:

Caesar cipher and cryptanalysis (frequency analysis)

Vigenere cipher and cryptanalysis (including why it works)

Affine cipher and cryptanalysis

Hill cipher (how to encrypt/decrypt, cryptanalysis)

AFDGVX cipher (how to encrypt/decrypt)

enigma (generalities, history)

terminology as covered in the slides of Wed Sept 2 (transposition cipher, block cipher, diffusion, etc. etc.)

DES (generalities, history)

modular arithmetic, to use in practice (addition, multiplication, powers, inverses using a multiplication table)

modular arithmetic, the mathematical rigor to the definition (e.g. why the operations are well-defined), definitions of invertible, inverses, unit group.

To know: the next class will be an introduction to Sage. I’ll have a worksheet ready to go; you’ll need a web browser to log in and participate.

To know: If you are interested in classical cryptography, a nice textbook with lots of history and details is “Secret History: The Story of Cryptology” by Craig P. Bauer. Here’s a super-cool short Numberphile video about Enigma Machine.

To do: If you missed the last few minutes of class on Wednesday (I went overtime by 5 minutes), review those last minutes on the canvas video.

To do: Compare your answers to the Exercises from the last daily to these solutions. If you still have any questions, contact me (or your peers) on discord (or email).

To do: Here are some exercises (tex) to hand in on the daily dropbox. You may wish to use the Hill Cipher Tools part of the course webpage, to avoid by-hand matrix calculations.

Purely, optionally, for fun: PSNAABAEDLEDNIONPLESMELUIOEAEEMATCO (Key: one inch and a standard can of beans.)