Lab 04 - Symmetric Cryptography

Introduction

The purpose of this lab is to introduce you to symmetric encryption algorithms and their uses and weaknesses. In addition to classic encryption (e.g. substitution ciphers such as the Vigenère cipher) we consider 3DES, AES and BlowFish.

Lab Goals

1. Decrypt a recently discovered Vigenère cipher, and determine why it is not safe to use classic encryption algorithms.

2. Encrypt and Decrypt using AES, 3DES and BlowFish.

3. Research password security applications.

Setup

You will need a Ubuntu machine (you may use your virtual machine if you like)

Lab Operations

Decipher the message below. Hint: The key is two words and a total of 15 letters long. For this, find your own tool online. For your convenience, the encrypted message is given below:

SEAN WIEUIIUZH DTG CNP LBHXGK OZ BJQB FEQT XZBW JJOY TK FHR TPZWK PVU RYSQ VOUPZXGG OEPH CK UASFKIPW PLVO JIZ HMN NVAEUD XYF DURJ BOVPA SF MLV FYYRDE LVPL MFYSIN XY FQEO NPK M OBPC FYXJFHOHT AS ETOV B OCAJDSVQU M ZTZV TPHY DAU FQTI UTTJ J DOGOAIA FLWHTXTI QLTR SEA LVLFLXFO

https://www.boxentriq.com/code-breaking/vigenere-cipher

Research: What password managers are available today? List the top 3 popular ones and reference sites that helped you determined which ones were popular. What algorithms do each of these use?

Top three Apps in order Algorithm(s) used

Show Me

1. In a Word Document include the key you believe unlocks the message above.

2. Encrypt the plaintext message with your southern username as the key and the AES-256-CBC algorithm (with the pbkdf2 option) provided by openssl. If your username is not long enough, repeat it with no spaces. Turn in the encrypted file with your Word Document. For example I used the following two commands to encrypt and decrypt the plain.txt file. If you use something different please document it in your Word document.

   1. openssl aes-256-cbc -pbkdf2 -a -in plain.txt -out cipher.txt

   2. openssl aes-256-cbc -pbkdf2 -a -d -in cipher.txt -out recovered.txt

3. In the same Word document, place a table containing the top 3 apps you identified, algorithms a link to your references.