A Glimpse of t he Hist ory of Crypt ography Cunsheng Ding Depar t ment of Comput er Science HKUST, Hong Kong, CHI NA Cunsheng Ding 1
P art I I : Machine Ciphers Cunsheng Ding 2
Enigma • Bef ore war broke out in 1939 t he Germans had planned a special way of keeping t heir communicat ions secr et . The army, navy and air f orce wer e t old t o encode t heir messages using cipher machines called ENI GMA. Cunsheng Ding 3
Enigma • Enigma could put a message int o code in over 150 MI LLI ON MI LLI ON MI LLI ON dif f erent ways. • The Germans believed t hat no one could crack t he Enigma code. But t he Allies knew t hat if t hey could, t hey would be able t o f ind out t heir enemy' s milit ary secr et s. Cunsheng Ding 4
Enigma • The Enigma machine looked like a t ypewrit er in a wooden box. An elect ric current went f r om t he keyboar d t hrough a set of rot ors and a plugboard t o light up t he ' code' alphabet . Cunsheng Ding 5
Enigma • At least once a day t he Ger mans changed t he or der of t he rot ors, t heir st art ing posit ions and t he plugboard connect ions. To decipher a message sent using Enigma, you had t o wor k out exact ly how all of t hese had been set . Cunsheng Ding 6
Enigma • I n t he 1930' s Polish cipher exper t s secr et ly began t o t ry t o crack t he code. J ust bef or e war br oke out t hey managed t o pass models and dr awings of Enigma t o Br it ish and Fr ench code- breakers. • Lat er Enigma was br oken. Cunsheng Ding 7
Sigaba • I t was suit ed f or f ixed st at ion secure communicat ions, and used by U.S. f or high- level communicat ions, was t he only machine syst em used by any part icipant t o remain complet ely unbroken by an enemy during World War I I . Cunsheng Ding 8
B-21 Machine by Boris Hagelin • Pat t erned on t he Enigma and produced f or t he Swedish General st af f , Boris Hagelin of Sweden developed t he B-21 machine in 1925. I t also had t he capabilit y t o be connect ed t o an elect ric t ypewrit er. Cunsheng Ding 9
BC-38 by Crypt o AG Zug • Boris Hagelin of Sweden developed a long line of cipher syst ems, beginning wit h t he B-21, B- 211, C-35, C-36, C- 38 (which lat er became Amer ica' s M-209). Cunsheng Ding 10
BI D 590 (Noreen) • The BI D 590 was a Brit ish built crypt o machine and was used by Canada' s f oreign service communicat ors at various diplomat ic missions t o communicat e wit h various government depart ment s. Cunsheng Ding 11
H-4605 (Crypt o AG) • The Crypt o AG H4605 was designed as an of f -line, keyboar d operat ed cipher machine wit h t win print ing (of cipher and plain t ext ) syst em wit h aut omat ic 5-let t er grouping. I t ' s a solid piece of equipment , almost ' bat t leship grade’. Cunsheng Ding 12
J apanese "Enigma" Rot or Cipher Machine Produced by Germans for Japanese Cunsheng Ding 13
Japanese Purple machine ♦ Electromechanical stepping switch machine modelled after Enigma ♦ Used telephone stepping switches instead of rotors ♦ Purple was broken with the help of MAGIC. ♦ Pearl Harbor attack preparations encoded in Purple, decoded hours before attack. Cunsheng Ding 14
KY-28 (Nest or) • The KY-28 was an analog, voice encr ypt ion device based on t ransist or cir cuit r y and was t he shipboar d/ air bor ne member of t he NESTOR f amily of equipment . Cunsheng Ding 15
Racal-Milgo 64-1027C Dat acrypt or • The Racal-Milgo 64- 1027C Dat acrypt or was used t o send and receive secure dat a via comput er. This is t he commercial version of t he KG-84, and has abilit y t o be loaded via t he KYK-13 Fill device. Cunsheng Ding 16
The “Clock Crypt ograph” • I t is basically a nicely implement ed Wheat st one cipher disk. I t was in act ive use in t he Danish ar med f or ces f r om 1934 (or a lit t le earlier) unt il ar ound 1948. Cunsheng Ding 17
People in Breaking Codes • Blet chley Par k was t he home of t he secr et Gover nment Code and Cypher School. This was t he cent re of Brit ish code-br eaking dur ing t he war. Cunsheng Ding 18
People in Breaking Codes • The code-breakers in Blet chley P ark were specially chosen f rom among t he cleverest people in England. Some were brilliant mat hemat icians or linguist s. • Alan Turing, a Cambridge mat hemat ician and code-breaker who helped t o invent one of t he world' s f irst comput ers at Blet chley Park. Cunsheng Ding 19
Comput er and Code Breaking • Colossus was built f or t he code- br eaker s at Blet chley Par k by post of f ice engineer s in 1943. • One of t he earliest comput er s. Cunsheng Ding 20
Comput er and Code Breaking • The comput er was as big as a room - 5 met res long, 3 met res deep and 2.5 met res high - and was made mainly f r om par t s used f or post of f ice t elephone and t elegr aph syst ems. Cunsheng Ding 21
Comput er and Code Breaking • This Cray XMP was donat ed t o t he museum by Cray Research, I nc. I t denot es t he newest era of part nership bet ween NSA and t he American comput er indust ry in t he employment of comput ers f or crypt ologic processes. Cunsheng Ding 22
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