Basic Classic Symmetric Beginner
The Affine Cipher
Learn about the Affine cipher, a generalization of the Caesar cipher that combines multiplication and addition to create a larger, but still breakable, keyspace.
14 min read
Tag
#Substitution Cipher
4 articles with this tag.
Basic Classic Symmetric Beginner
The Atbash Cipher
Learn about the Atbash cipher, one of the oldest known substitution ciphers, where each letter is mirrored to the opposite end of the alphabet.
11 min read
Basic Classic Symmetric Breakers Advanced
Breaking the Substitution Cipher
A monoalphabetic substitution key is one arbitrary permutation of 26 letters: 26! of them, far too many to brute force and immune to Kasiski or the Index of Coincidence since there's no repeating key. Here's how frequency analysis and a hill-climbing search crack it anyway.
26 min read
Basic Classic Symmetric Beginner
The Monoalphabetic Substitution Cipher
Learn about the monoalphabetic substitution cipher, the general family of ciphers that Caesar, Atbash, and Affine are all special cases of, and why its huge keyspace still isn't enough to make it secure.
12 min read