Substitution

Explanation

A substitution cipher is a method of encryption where each letter in the plaintext is replaced by another letter or symbol according to a predetermined set of rules. In other words, it substitutes each plaintext character with another character.

Substitution ciphers are among the simplest forms of encryption and have been used throughout history for secret communication.

However, they are generally less secure compared to modern encryption techniques and are vulnerable to various cryptanalysis methods, such as frequency analysis, which exploits patterns in the ciphertext to reveal information about the plaintext.

Despite their vulnerabilities, substitution ciphers are often used in educational settings to introduce basic concepts of cryptography.

Facts

The Caesar cipher is a type of substitution cipher, where the alphabet is just shifted rather than completely shuffled.

Substitution ciphers are some of the earliest known encryption methods.

Because of their nature they are easy to break using techniques such as frequency analysis.