1. Explain briefly how the following substitution ciphers can be broken: Caesar cipher, Simple substitution cipher, Vigenere cipher.
A Caesar cipher can be broken by shifting all of the letters in the encrypted message over by a certain amount. A simple substitution cipher can be broken using frequency analysis to determine which characters are used most often. A Vigenere cipher is more complex, but can be broken using a polyalphabetic frequency analysis table.
2. Define symmetric encryption.
Symmetric encryption is a type of encryption that uses the same key for both encryption and decryption.