Breaking the Mono-alphabetic Substitution Cipher
- Substitution Cipher - Wikipedia
- Introduction to Cryptography and Substitution Ciphers - Khan Academy
- Classical Cryptography Techniques - GeeksforGeeks
- Frequency Analysis in Cryptography - Practical Cryptography
- Caesar Cipher and Substitution Ciphers - Stanford CS 106B
- Notes on MonoAlphabetic Substitution Cipher