OpenLab code-breaking assignment (in teams)

For this assignment, form teams of 2-3 students. There are two goals for this assignment:

1. Conduct a conversation publicly on the OpenLab with your partners entirely in code.
2. Break another team’s code to decipher their messages.

Before starting your conversation, you and your partner(s) must choose how you will encrypt your messages. Read pages 294-297 and, together with your teammates, choose a shift cipher, an affine cipher, or a block cipher to use. Keep this information private. Decide who will post the first message.

One team member will post the first message as a new post on the OpenLab. Title your post “Code-breaking” and the names of all the team members (not encrypted). Select the “Code-breaking” category from the right-hand side of the screen. The message can be as long as you want, but it must be at least two sentences long and must be entirely encrypted. It will look something like:

L ZLOO EH UHDOOB KDSSB LI BRXU HQFRGHG PHVVDJHV DUH VLOOB MRNHV RU IXQQB VWRULHV. MXVW PDNH VXUH WKDW WKHB DUH QRW WRR LQDSSURSULDWH!

After the first message is posted, other team members can add their encrypted responses as comments on their teammate’s post. Every team member must post at least one message. Messages don’t need to say anything in particular. You can tell a story together or ask each other questions. You can be silly or you can be serious. Keep posting encrypted messages until someone else breaks your code.

After enough encrypted messages have been posted, try breaking another team’s code. If you break it, post a comment on their thread with the decrypted messages along with the kind of cipher they chose, and the information you needed to decrpyt it. If you and a partner work together to break another team’s code, make sure to credit them in your post. You can try breaking as many other teams’ codes as you like, but you may only post the decrypted code for one team.

First post due by Tuesday, April 11. All teammates’s comments due by Thursday, April 13.

We’ll see how many codes have been broken by our first class meeting after spring break!

You might find the Khan Academy unit on cryptography (including videos) to be useful.