Appreciate that cryptography is a broad term that includes tools for providing a wide range of security properties
Give examples of scenarios in which secrecy, authentication and data integrity would be desirable
Describe the basic structure and requirements of a symmetric encryption scheme, vs asymmetric
[confirm this is what the notes says]
Symmetric:
- the same key is used to encrypt or decrypt a message
- both Alice and Bob hold a copy of the key
- if the key is stolen, game over
Asymmetric:
- a pair of different keys used for encryption and decryption
- Bob shares the encryption key publicly; only the intended message recipient holds the decryption key
- it’s fine if the public key is “stolen”; if private key is stolen then game over
Describe the Caesar Cipher, perform encryption and decryption using the Caesar Cipher and discuss its weaknesses
Describe the Substitution Cipher, perform encryption and decryption using the Substitution Cipher, and discuss its weaknesses
Define a brute force attack on a symmetric encryption scheme
Describe how to use frequency analysis to attack a Substitution Cipher
Appreciate that an attack is said to break a cipher if it can be carried out faster than a brute force attack on the same cipher
