The HX-63 was an advanced rotor machine

Rotor machine

In cryptography, a rotor machine is an electro-mechanical device used for encrypting and decrypting secret messages. Rotor machines were the cryptographic state-of-the-art for a prominent period of history; they were in widespread use in the 1920s–1970s...

 designed by Crypto AG

Crypto AG

Crypto AG is a Swiss company specialising in communications and information security. With headquarters in steinhausen, the company is a long-established manufacturer of encryption machines and a wide variety of cipher devices...

, who started the design in 1952. The machine had nine rotors, each with 41 contacts. There were 26 keyboard inputs and outputs, leaving 15 wires to "loop back" through the rotors via a different path. Moreover, each rotor wire could be selected from one of two paths. The movement of the rotors was irregular and controlled by switches. There were two plugboards with the machine; one to scramble the input, and one for the loop-back wires. The machine could be set up in around 10⁶⁰⁰ different configurations.

Only twelve of these machines were manufactured, and it was used by only one department of the French Government.

External links

• Jerry Proc's pages — photographs and a brief description
• Notice of a past eBay auction of an HX-63
• John Savard's discussion on the machine