Cryptanalysis
Cryptanalysis is science, art, and practice of cracking cryptographic systems.
- using techniques other than brute force to attempt to uncover a key
- aka academic or knowledge-based code breaking
- some techniques are used to test efficacy of cryptographic algorithms
- common to test hashes for collisions
Methods
Kasiski Examination
Kasiski Examination is a method of attacking poly-alphabetic substitution ciphers.
- aka Kasiski’s test or Kasiski’s method
- can be used to deduce the length of the keyword used
- once discovered, the ciphertext is lined up in
columns, where is the length of the keyword - each column can be treated as mono-alphabetic substitution cipher and each column can be cracked with frequency analysis