Hugo Alexander Koch (9 March 1870,

Delft Delft () is a List of cities in the Netherlands by province, city and Municipalities of the Netherlands, municipality in the Provinces of the Netherlands, province of South Holland, Netherlands. It is located between Rotterdam, to the southeast, ...

– 3 March 1928,

Düsseldorf Düsseldorf ( , , ; often in English sources; Low Franconian and Ripuarian: ''Düsseldörp'' ; archaic nl, Dusseldorp ) is the capital city of North Rhine-Westphalia, the most populous state of Germany. It is the second-largest city in th ...

) was a Dutch inventor who conceived of and patented an idea for machine

encryption In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can decip ...

— the

rotor machine In cryptography, a rotor machine is an electro-mechanical stream cipher device used for encrypting and decrypting messages. Rotor machines were the cryptographic state-of-the-art for much of the 20th century; they were in widespread use in the 19 ...

, although he was not the first to do so. He is sometimes erroneously credited as the originator of the Enigma machine, although this has been shown to be the work of German engineer

Arthur Scherbius Arthur Scherbius (30 October 1878 – 13 May 1929) was a German electrical engineer who invented the mechanical cipher Enigma machine. He patented the invention and later sold the machine under the brand name Enigma. Scherbius offered uneq ...

. Koch filed for his rotor machine patent on 7 October 1919, and was granted

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

patent 10,700 (equivalent to ), held by Naamloze Vennootschap Ingenieursbureau Securitas in

Amsterdam Amsterdam ( , , , lit. ''The Dam on the River Amstel'') is the Capital of the Netherlands, capital and Municipalities of the Netherlands, most populous city of the Netherlands, with The Hague being the seat of government. It has a population ...

. No machine was built from his patents, and, in 1927, he assigned the rights to

, the inventor of the Enigma machine. Scherbius had developed the idea of rotor machine encryption independently from Koch, and had filed for his own patent in 1918. Bauer (1999) writes that Scherbius bought Koch's patents "obviously not because he did not own patents before; presumably he wanted to protect his patents".

References

Friedrich L Bauer Friedrich Ludwig "Fritz" Bauer (10 June 1924 – 26 March 2015) was a German pioneer of computer science and professor at the Technical University of Munich. Life Bauer earned his Abitur in 1942 and served in the Wehrmacht during World War ...

, "An error in the history of rotor encryption devices", Cryptologia 23(3), July 1999, page 206. * David Kahn, The Codebreakers, 1967. {{DEFAULTSORT:Koch, Hugo 1870 births 1928 deaths 20th-century Dutch inventors Dutch cryptographers People from Delft

See also

References