Background

Encryption is used to pass information from one person to another person in a way that ensures the confidentiality of the information.

Encryption can be very difficult to break since the person performing the encryption could have used many different techniques to encrypt the data. Once approach to encryption which is based on simple substitution replacement of each letter, is to use the fact that certain letters in English prose, occurs more often than other letters.

This module will provide a lecture on cryptography, a module showing the decryption, and some follow-up discussion questions for the student”.

In English prose there is a certain frequency with which letters occur. The table below gives an example of this.

Using this information, we can perform a frequency analysis of encrypted text to determine the frequency of letters in the encrypted text. Using these two tables we will be able to determine what substitutions were made to obtain the encrypted text.

Giraffe Frequency Table VS. Encrypted Frequency Table

Lecture Topics:

Lecture of module 2 will focus on: Frequency analysis in social science research, frequency distribution table creation with Excel, SPSS, Cryptography, & frequency analysis & encryption.