04 What is Substitution?

In cryptography, substitution is one of the two basic encryption classes.

The characters are changed according to a fixed procedure.

If only one alphabet is used, this is called monoalphabetic substitution, otherwise polyalphabetic substitution.

If only one character is substituted at a time, it is called a monographic substitution; otherwise it is called a bi-/polygraphic substitution.

GCWizard knows the following substitution encodings: