Editing Ciphertext (section)

=== Historical ciphers ===
Historical pen and paper ciphers used in the past are sometimes known as [[classical cipher]]s. They include:

* [[Substitution cipher]]: the units of plaintext are replaced with ciphertext (e.g., [[Caesar cipher]] and [[one-time pad]])
** [[Polyalphabetic substitution|Polyalphabetic substitution cipher]]: a substitution cipher using multiple substitution alphabets (e.g., [[Vigenère cipher]] and [[Enigma machine]])
** [[Polygraphic substitution]] cipher: the unit of substitution is a sequence of two or more letters rather than just one (e.g., [[Playfair cipher]])
* [[Transposition cipher]]: the ciphertext is a [[permutation]] of the plaintext (e.g., [[Rail fence|rail fence cipher]])

Historical ciphers are not generally used as a standalone encryption technique because they are quite easy to crack. Many of the classical ciphers, with the exception of the one-time pad, can be cracked using [[Brute force attack|brute force]].