Substitution Ciphers

In general, substitution ciphers are those in which characters from the plaintext are simply substituted (replaced in a specific manner) with another set of characters, which results in the ciphertext.

A list of Substitution ciphers

• Homophonic Substitution Cipher

  The Homophonic Substitution cipher is a substitution cipher in which single plaintext letters can be replaced by any of several different ciphertext letters. They are generally much more difficult to break than standard substitution ciphers.

• Base64 Cipher

  Base64 isn't really a cipher, but I see it used all the time for "enciphering" text, so it gets an honorary mention.

A few variations

• Monoalphabetic Substitution Ciphers

  • Atbash Cipher
  • ROT13 Cipher
  • Caesar Cipher
  • Affine Cipher
  • Baconian Cipher
  • Polybius Square Cipher
  • Simple Substitution Cipher
  • Codes and Nomenclators Cipher

• Polyalphabetic Substitution Ciphers

  • Autokey Cipher
  • Beaufort Cipher
  • Porta Cipher
  • Running Key Cipher
  • Vigenère and Gronsfeld Cipher
  • Enigma Cipher

• Polygraphic Substitution Ciphers

  • Four-Square Cipher
  • Hill Cipher
  • Playfair Cipher