Handy References

• Wikipedia page on letter frequency

Assignment 1 Goals:

• Gain experience in cryptanalysis
• Write a program to determine character frequencies
• Work a bit on writing skills.

For this assignment, you will decrypt a message encrypted using a substitution cipher. Simple enough, right?

Each of you will receive a different ciphertext, encrypting a different text, encrypted using a different key. Here are your texts:

• Kobe Collison
• Michael Foley
• Lex Francis
• Jillian Hanson
• Alex Hyman
• Jacob Libby
• Dylan Peczka
• Alex Pinette
• Alexis Romer
• Matt Sullivan
• Alex Vazquez

You should submit a .zip file containing the following files:

• A file containing the number of occurences of each letter in the text, ordered from most frquent letter to least frequent letter
• A file containing the program you used to produce the file above (if you say you did it by hand, I will not believe you)
• A file containing the decrypted text
• A file containing the encryption key I used. This file should contain two columns, the first column should be the letters from a to z, the second column should indicate the letter used to encrypt the letter to its left.
• A file containing the general steps you used to cryptanalyse your text. You can just outline the general steps, no need to go in too many details, a few paragraphs should suffice.