Ancient Web: Cipher Machines and Cryptology Kept Cold War Codebooks Readable

Part of the Ancient Web Collection.

A photograph of an Enigma machine can tell you what a secret looks like. Dirk Rijmenants wanted to explain how the machines actually worked—and what operating one demanded of its users.

Visit Cipher Machines and Cryptology.

Rijmenants says in the site's history that he founded the project in 2004. The material covers wartime and Cold War encryption equipment alongside manual ciphers, intelligence history, and signals intelligence. A substantial section examines the Enigma family, including message procedures, U-boat codes, and rotor operation.

The index branches well beyond the most famous German machine. There are pages for the American KL-7 ADONIS, Hagelin B-21 and C-52, the M-209, numbers stations, one-time pads, and photographic profiles of rare equipment.

The timeline is a mechanical museum

The cipher-machine timeline starts with the American M-94 cipher cylinder and Edward Hebern's early rotor machine, then follows the development of Enigma, Hagelin pinwheels, teleprinter systems, and the high-security machines of the Second World War.

Each entry offers a compact operating explanation and links to deeper sources. The project also hosts software simulators intended to demonstrate the behavior of historical machines. Their existence and claimed authenticity are described on the website; they were not downloaded or executed for this article.

In its about page, the site stresses original records from archives, museums, and fellow researchers, and points readers toward preserved Internet Archive copies if old links break. It offers English and Dutch versions, written separately rather than relying on automatic translation for specialized technical vocabulary.

There is a preservation ethic behind the detailed interface. Rijmenants acknowledges that even long-running websites can disappear, asks visitors to report broken citations, and provides instructions for locating archived external sources. The website was still being revised in September 2026.

This is a history of cryptographic practice, not a recommendation to use retired cipher machines for secure modern communication. It is also distinct from modern mathematical cryptography textbooks: its focus is the physical equipment, its operators, and the documents that explain both.

Explore the machine timeline and the project's history.

Part of the Ancient Web Collection.