6.06 Cryptography Basics

6.6 Cryptography Basics Curriculum Page

1. Explain briefly how the following substitution ciphers can be broken: Caesar cipher, Simple substitution cipher, Vigenere cipher.
   • Caesar cipher can be broken down by looking for repeats in the message and then using those repeats to discover the key that was used. Simple substitution cipher can be broken down by using frequency analysis. As for Vigenere cipher, it can be cracked by analyzing the patterns mathematically. To start off, the length of the key should be identified and then from this information the specific key can be found.
2. Define symmetric encryption.
   • Symmetric encryption is encryption that uses the same key to encrypt and decrypt a message.