CSCI 554 Digital Forensics

Assignment

Fall 2019

Total Points: 100

Question 1 (30 points)

ROT13 is a variation on the Caesar cipher. It is a very simple method for hiding textual information by replacing each alphabetic character with the letter thirteen places after it. For example, the letter ‘' becomes ‘n’. One good characteristic of this cipher is that it can be used for both hiding information and decoding it. Write a Python function for this cipher. The function should be called rot13 and takes as an argument the path of a text file. The function will read the text file, apply the cipher on its contents and write the ciphered contents to a text file called cipher.txt. Your code should make use of a dictionary data structure to solve this problem. Make sure that your program handles special cases.

Question 2 (70 points)

Write a python program (.py) that traverses a directory and calculates the digital fingerprints (MD5, SHA1, and SHA256) of all the files in the directory. The program should ask the user for the name of the directory and whether the program needs to recursively go though all the other directories inside the given directory. The program proceeds to calculate the MD5, SHA1, and SHA256 values for each file and saves the result in an Excel document. The Excel document should have the following columns: file name, MD5, SHA1, and SHA256. Each directory should have a separate sheet. Make sure that your program handles special cases. The following link has a good introduction on how to work with Excel files:

https://automatetheboringstuff.com/chapter12/