Nomenclator is a special encryption system consisting of several different simpler encryption
systems used together during the encryption.
This type of encryption was very popular and was used for a long time period.
It was used from the fourteenth to the nineteenth century.
The design of these systems was very variable. It is possible to find examples from small (very simple) instances to very complex ones.
A nomenclator mostly contains a substitution of letters (monoalphabetic or homophonic substitution)
in a combination with substitution of n-grams (bigram and/or trigram substitution), codes and nulls.
It is not widespread, but some nomenclators contain a polyalphabetic substitution, too.
For more information about Nomenclator systems read the articles published in the Proceedings of the 4th and 5th International Conference on Historical Cryptology.
This module also contains an online database of digitized cipher keys with a public API. All the cipher keys are accessible without the need for registration.
Cipher Creator is an online tools designed to create, use, and share nomenclator cipher keys.