For Fri:
 Don’t forget FCQs are open! I really appreciate your feedback and read them very carefully.
 There were a lot of administrative announcements in yesterday’s daily, you might want to review them.
 Compare your last daily to the solutions.
 I have intentionally NEVER done this all semester, but I had ten more minutes of riveting information to share about latticebased cryptography, so I made a bonus 10minute video. (I’ve allowed myself this luxury because I really don’t want to delay coding theory.) Watch it here. The lecture notes include this material.
 A RingLWE ciphertext chain! You may want to review the course video on canvas and I’ve made careful overleaf notes. Here’s what you’ll need:

 Our general setup with be the prime p = 100003 and n=8. We will use l=10. This will allow us enough room for each coefficient to hold one letter from the texttointegertotext tools. Because there are 8 coefficients, you can store 8 letters.
 Answer the question “what’s the best part of crypto?” in 8 letters or less, and store it as an element of the ring $R_p$ using one letter per coefficient (coefficient of $x^7$ is the first letter, coefficient of $x^6$ is the second letter, etc.). This will be your message.
 At the RingLWE Tools page you’ll see how to initialize the polynomial ring, and you’ll have two functions that generate short and random elements. In our case, “short” means coefficients from {1,0,1}.
 First, generate your own private/public key pair and post the public key (g,B) on the discord #ciphertexts channel. Keep your secret key for later (e.g. in a text file). Important note: discord normally interprets asterisks and stuff in special ways; to make it easier on everyone, surround your polynomials with backticks ` when pasting into discord, and it will post it verbatim. This will make cuttingandpasting to/from Sage easier.
 Now, encrypt your message to the most recent unused public key on the #ciphertexts channel. Post your message (K,C) on the #ciphertexts channel and mention the appropriate person.
 Wait until someone sends you a message. When this happens, decrypt it using your secret key, and announce their favourite part of crypto on #ciphertexts, mentioning them so they can confirm.
 Post your record of the events/computations to the canvas dropbox.
