3 Classic Methods

Transposition Cipher reorder the characters (of the bits) of a plaintext following some scheme or a geometric figure, e.g.a two-dimensional matrix. An example is Row Transposition (with a fixed matrix).

There are four kinds of Substitution Cipher:

Simple Substitution: Every characters of the plaintext is replaced by a characters of the ciphertext, e.g. Shift Cipher, Substitution Cipher, Affine Cipher.

Homophone Substitution: Every characters of the plaintext can be replaced by different characters of the ciphertext, e.g. Vigenère Cipher.

Polyalphabetical Substitution: The plaintext characters are ciphered in a special order (e.g., periodically) through different transformations.

Polygram Substitution: Whole blocks of plaintext characters are replaced.

3.1 Row Transposition