For Monday, December 9th, 2024

  1. Please do your FCQs!  Please go back two daily posts and check all the end-of-semester announcements on that post.  Make sure you are ready to hand in your self-eval sheet.
  2. Note: there was a typo in the solutions (not exam) for Test #2, the baby-step-giant-step problem. I don’t think there was any grading error as a result of this, but if you are concerned, please re-download the file from the website and check. It has now been fixed in the solutions set.
  3. Test #4 solutions are up (Archive tab).
  4. Written replacement problems are up on canvas — the PDF of the replacement problems is on the corresponding dropbox page.  Reminder:  you can replace one computational problem on each of the first three tests.  If you wanted to replace a score of 6 or below, that was in person; but for scores 7 and above, you can do a written replacement, due on exam day (I extended the deadline), so it can be helpful for studying.
  5. The final videos (last day) are up (they are on the Archive tab above), and they cover two aspects of coding theory.  One is finishing up the cyclic codes were were discussing.  The other is the McEliece post-quantum cryptosystem.  I will not ask you to do computational McEliece, just to understand the general idea (what is the hard problem?  what is the secret and public key? etc — I won’t quiz you on the exact equations either).
  6. As I’ve mentioned, between now and the exam, I will take requests for further material demonstrating review problems, answering questions, reviewing topics, etc., just be specific please.  Please specify if you’d like me to write up something in the textbook or make a video.  I’ll do as many as I can, as a compensation for my physical unavailability during the last week before the exam.  I’ll also try to be responsive on discord, but I’m going to be in New Zealand so keep in mind I might be sleeping while you’re awake!  Your TA will proctor the final.
  7. If you are having any special circumstances for the final, e.g. extra time, please make sure you know *when* and *where* you need to be.  Contact me if you are unsure.
  8. For Monday, here are some early-semester review problems to get you rolling for the final:
    1. Find the GCD of 27 and 79.
    2. Solve 27x + 79y = 1 using the extended euclidean algorithm.
    3. Compute 2^27 modulo 19 using successive squaring.
    4. Explain how you can tell 5 is invertible modulo 191.
    5. Find the inverse of 5 modulo 191 (this uses extended euclidean).