Classical cipher

In cryptography, a classical cipher is a type of cipher that was used historically but, for the most part, has fallen into disuse. In contrast to modern cryptographic algorithms, most classical ciphers are very simple to break with modern technology, and usually can also be solved by hand. The term includes the simple systems used since Greek and Roman times, the elaborate Renaissance ciphers, World War II cryptography such as the Enigma machine, and others.

Conversely, modern strong cryptography relies on new algorithms and computers developed since the 1970s.