Editing Substitution cipher (section)

== In modern cryptography ==
Substitution ciphers as discussed above, especially the older pencil-and-paper hand ciphers, are no longer in serious use. However, the cryptographic concept of substitution carries on even today. From an abstract perspective, modern bit-oriented [[block cipher]]s (e.g., [[Data Encryption Standard|DES]], or [[Advanced Encryption Standard|AES]]) can be viewed as substitution ciphers on a large [[Binary numeral system|binary]] alphabet. In addition, block ciphers often include smaller substitution tables called [[S-box]]es. See also [[substitution–permutation network]].