SUNY Geneseo Department of Computer Science


Essay 1—Breaking a Code

Intd 105, Spring 2014

Prof. Doug Baldwin

Draft by Tuesday, January 28
Complete by Wednesday, January 29
Grade by Tuesday, February 4

Purpose

The goal of this exercise is to give me a sense of how you write now, at the start of this course, and to give you a gentle introduction to what I will expect of writing assignments throughout the course.

Background

This exercise asks you to attack a substitution cipher and write about how you did it. We talked about substitution ciphers and ways to attack them in our January 23 class meeting. There are also lots of online tools for analyzing messages enciphered with a substitution cipher, for example the ones at Simon Singh’s “Black Chamber” website. You are welcome to use these tools in this exercise.

Exercise

In very short form, your assignment is to write about how you decipher a message that has been enciphered with a substitution cipher.

The enciphered message is as follows:

JVUNYHABSHAPVUZ FVB OHCL IYVRLU FVBY MPYZA ZBIZAPABAPVU JPWOLY AOPZ LEHTWSL DHZ H ZPTWSL ZVYA VM ZBIZAPABAPVU JHSSLK H JHLZHY JPWOLY DOPJO BZLZ H ZOPMALK HSWOHILA HZ AOL JPWOLY HSWOHILA ZPTWSL VY UVA FVB ZLLT AV IL VU FVBY DHF AV ILJVTPUN HU LEWLYA JVKL IYLHRLY

See if you can decipher the message, i.e., translate it back into plain English. As you do so, think about how you are doing it: what clues you spot that help you understand how the message is enciphered, what guesses you try out, which guesses work and which ones don’t, etc.

Write about two pages (500 to 600 words) describing how you went about deciphering the message, and what the result you got was.

I expect you to make a serious effort to decipher the message; I hope most of you will decipher it as a result. However, if you try but can’t decipher the message, that’s OK—you can still write about the thought processes you went through and why they didn’t work.

I obviously expect your essay to explain your thinking and present the deciphered message (if any) that you ended up with. I also expect the reader to be able to follow your thought processes easily. This requirement basically boils down to clear writing, at every level from the overall organization of the essay to the details of grammar and word choice. This is the one essay you will write for this course that is not a persuasive essay, i.e., it is the one in which you are not really stating and defending a thesis. I therefore don’t require you to write much of an introduction or conclusion to the essay. I would certainly prefer that you use most of your space to explain how you broke the code rather than that you use very much of that space for introductory or concluding remarks.

Follow-Up

In next Tuesday’s class (January 28), you will do “peer critiques” of each other’s draft essays. In other words, I will ask you to exchange essays with other students in the class, read them, and discuss the writing in small groups. To do this, please bring 2 printed drafts of your essay to class on that day. These drafts should be complete enough that your fellow students can give you useful feedback on them, but do not have to be nearly what you eventually turn in.

Turn in your essay by emailing it to me (baldwin@geneseo.edu). The email must be timestamped by 11:59 on the “Complete By” date above. You can write your essay using any common word processor.

Finally, I will meet face to face with each of you to discuss your essays and give you your grades. Please sign up for a half hour meeting with me, to be held some time between when you turn in your essay and the end of the day (5:00 PM) on the “Grade By” date above. You can sign up for these meetings on the schedule outside my office. The schedule is divided into 15-minute blocks, so sign up by writing your name across two consecutive blocks; I may have schedules for several weeks posted, so be careful that you are signing up for the day you intend. If you prefer not to sign up on the paper schedule, you can use Google calendar instead.