Csec 630 Lab Assignment 1

2/23/14

CSEC 630 – Lab Assignment

Q1. Which tool or technique from the above list would be most effective for a

cryptanalyst to use to decipher a text encrypted with the Caesar cipher, and why?

Floating frequency is the most effective tool used to decipher a text encrypted with the Caesar cipher. Floating frequency replace one letter of the plaintext with another to produce the cyphertext, and any particular letter in the plaintext will always, in the simplest and most easily breakable of these cyphers, turn into the same letter in the cypher. For instance, all E's will turn into X's. Floating frequency is based on the fact that certain letters, and combinations of letters, appear with characteristic frequency in essentially all texts in a particular language (Introduction To Codes, Ciphers, & Codebreaking, 2010).

Q2. What do you notice about the histogram results when text is encrypted with the

Vigenère cipher in comparison to the results of the Caesar cipher? Why is this the

case?

I’ve notice between the two ciphers the Caesar cipher was easier to see a pattern between the alphabets oppose to the Vigenere cipher which was much harder to see a pattern. The Caesar cipher would be much easier to crack because one would be able determine a pattern rather than the Vigenere cipher which would be much harder to break.

Q3. There is an error in the following ciphertext representation of this quote, what is

it? What should the correct ciphertext be? (Hint: when using the CrypTool there are several

ways to decode one that you can use is “Playfair” encipher option, the plaintext and key

provided in the lab information, and DESELECTING the “separate duplicate letters only within

pairs” option)

SDAHFOWGRABSSRERIVBYBSCIMQTFNIVETGHBSNQCNCSDTDHBSNQCD

ECNICIFCTIC

The error is the ciphertext included additional alphabets located below in Red:

THE DIFXFERENCE BETWEXEN STUPIDITY AND GENIUS IS THAT GENIUS HAS ITS LIMITS

The...