Cryptography During World War II

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Cryptography During World War II

• Wednesday, December 7, 2005
• CS 4235 A
• Mohammad Abolfathian
• Ashley Durham
• Michel Mansour
• Michael Norris
• Kalpit Patel
• Vimal Patel

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Agenda

• Discuss context of war and cryptography.
• German encryption systems.
• Battle of the Atlantic.
• Bletchley Parks successes.
• Japanese cryptography.
• Influences on battles in the Pacific
• Allied invasion of France.
• Victory.
• Legacy left by the conflict.

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Trivia Question!

• What happened on this infamous date, sixty-four
  years ago?
• /-5 EC points on your final average!!! N-P
  Approved!
• Note EC not really approved.

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Introduction to WWII

• 1939-1941 Germany invades Poland, France, and
  Russia
• Battle of the Atlantic
• July Oct 1940 - Battle of Britain
• Dec 1941 America enters the war
• 1942-1944 Allied landings in Africa, Italy and
  France
• May 1945 - VE Day

• 1937 Japan continues expansion in China and
  Pacific
• Dec 1941 Pearl Harbor
• 1942 Battle of the Coral Sea, Battle of Midway
• 1943-1945 Allied island hopping
• Aug 1945 Atomic bombs detonated
• Sep 1945 VJ Day

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Cryptography in the Conflict

• Both sides realize need for secure communications
• Cryptographic equipment deployed
• Focused intelligence effort on attacking these
  systems
• Encrypted traffic broken
• High impact on the war
• Laid foundation for modern cryptography and
  computing

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Enigma Fish

• Enigma
• Rotor-based encryption device
• Poly-alphabetic Substitution Cipher
• Introduced 1920s
• Evolved during war
• Fish (Lorenz or T52)
• Stream Cipher (more than a PNGXOR)
• Deployed 1940
• Broken early 1942 at Bletchley Park
• Used by German High Command

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Battle of the Atlantic/Britain

• Fought 1939-1945
• German offensive against Allied shipping
• U-boat tactics relied heavily on Enigma
  communication
• By 1941, most traffic was read by Allies

• Blitz Jul-Oct 1940
• Intelligence provided command view of battle
• Enigma traffic defeated regularly
• Maintained Allied foothold on Europe

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Bletchley Park

• British code-breaking headquarters
• Occupied by British intelligence in August, 1939
• Brilliant mathematicians
• Alan Turing
• Important cryptanalytical breakthroughs
• Cracking Enigma
• Colossus

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Bombes Colossus

• Bombe (1940)
• Enigma killer
• First built by Polish scientists in 1937
• British built their own in 1940
• Enigma's fundamental flaw no character encoded
  as itself
• Factory-style attack
• Colossus (1943)
• First programmable computer
• Designed to break Fish
• Human weeks vs. Colossus hours
• Produced intelligence used in the precise timing
  of D-Day

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Purple

• Japanese diplomatic cryptosystem
• Intelligence stored in purple binders
• Electromechanical step-switching device
• Used from 1939 to the end of the war
• Poor key choices allowed it to be broken

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JN-25

• Japanese Military code
• Broken after the attack on
  Pearl Harbor
• Provided intelligence that
  aided in the U.S. victories
  at the Battle of Midway
• and the Battle of Coral Sea
• Provided intelligence that provided the U.S. with
  the location of Yamamoto Isoroku that allowed his
  assassination

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Pacific Theater

• Battle of Coral Sea
• May 1942
• Major turning point in
• the Pacific War
• First carrier naval engagement
• Indecisive
• Battle of Midway
• June 1942
• Prevented Japan from
• becoming a hegemony
• in the Pacific

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D-Day

• June 6, 1944
• Timing dictated by intelligence
• Several German battalions were expected to be
  absent
• Intelligence turned out to be incorrect
• Nature of intelligence

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Victory

• V-E Day
• May 8, 1945
• V-J Day
• August 15, 1945
• Intelligence directly led to both victories.
• Significantly shorted duration of conflict

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Conclusion

• Intelligence and cryptanalysis was decisive in
  both theaters
• Programmable computers born
• Modern cryptography and Computing linked
• Foundations for applied cryptography

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Thank you. Any questions?