# Substitution Ciphers

From MRL Wiki

Substitution Ciphers work by encoding each individual character in plaintext into ciphertext according to some correspondence table.

## [edit] Cryptanalysis

Strength of substitution ciphers can be reduced by looking for repeated patterns, common initial and final letters. There are several approaches to breaking Substitution Ciphers:

- Reversing of the substitution algorithms itself by finding patterns.
- Brute Force approach is often unfeasible due to 26! permutations of a particular ciphertext message, but in simpler cases it could work as a shortcut.
- Word and letter frequency analysis. The most common letters in English language are E, T, O, and A which should also appear in weak substitution ciphers.