OMI (machine)

OMI was a series of rotor cipher machines , the first model of which, OMI Alpha, came into being in 1939, i.e. just before the Second World War . Sometimes it is also referred to as the "Italian Enigma ". After the war, around 1954, i.e. during the early days of the Cold War , the OMI Criptograph followed , then the OMI Cryptograph-CR towards the end of the 1950s and finally the OMI Cryptograph-CR Mk II in the early 1960s . They were all developed and manufactured by the Italian company Ottico Meccanica Italiana (OMI for short; German  “ Italian Optomechanics ” ), which was founded in Rome in 1926 by Umberto Nistri (1895–1962) .

OMI Alpha

The OMI Alpha was constructed similar to the German Enigma D , but had five rotors (and not just four).

OMI criptograph

The OMI Criptograph was the post-war version of the Alpha and cryptographically differed little from it.

OMI Cryptograph-CR

The OMI Cryptograph-CR was the technically advanced successor of the Criptograph , which differed little from its predecessors in terms of cryptography.

OMI Cryptograph-CR Mk II

The OMI Cryptograph-CR Mk II (also: Cryptograph-CR-2 ) was the technically most advanced model of the series and at the same time its completion. Like its predecessors, the CR-2 also has five interchangeable rotors. It also includes a stator and reflector, both of which are non-interchangeable and do not rotate, but both adjustable to 26 different positions. A cryptographic strength of all OMI models is the irregular switching of the rotors.

literature

• Herbert Avram: Ottico Meccanica Italiana Criptograph-Wiring (PDF; 450 kB; English) Formerly secret description of the OMI-Criptograph, NSA , 1954. Retrieved on June 2, 2017.
• Friedrich L. Bauer : Deciphered Secrets. Methods and maxims of cryptology. 3rd, revised and expanded edition. Springer, Berlin a. a. 2000, pp. 117 and 143.

Web links

• OMI Alpha at the Crypto Museum , accessed May 24, 2017.
• OMI Criptograph in the Crypto Museum , accessed on May 24, 2017.
• OMI Cryptograph-CR in the Crypto Museum (English), accessed on May 24, 2017.
• OMI Cryptograph-CR Mk II in the Crypto Museum (English), accessed on May 24, 2017.
• OMI at Jerry Proc, accessed May 24, 2017.

Individual evidence

1. ↑ OMI at Jerry Proc , accessed May 24, 2017.
2. ↑ OMI Alpha in the Crypto Museum (English), accessed on May 24, 2017.
3. ↑ OMI Criptograph in the Crypto Museum (English), accessed on May 24, 2017.
4. ↑ OMI Cryptograph-CR in the Crypto Museum (English), accessed on May 24, 2017.
5. ↑ OMI Cryptograph-CR Mk II in the Crypto Museum (English), accessed on May 24, 2017.