Cryptography During World War II: Cryptography During World War II Wednesday, December 7, 2005 CS 4235 A Mohammad Abolfathian Ashley Durham Michel Mansour Michael Norris Kalpit Patel Vimal Patel


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


Trivia Question!: 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.


Introduction to WWII: 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


Cryptography in the Conflict: 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


Enigma & Fish: 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 PNG+XOR) Deployed 1940 Broken early 1942 at Bletchley Park Used by German High Command


Battle of the Atlantic/Britain: Battle of the Atlantic/Britain Blitz – Jul-Oct 1940 Intelligence provided command view of battle Enigma traffic defeated regularly Maintained Allied foothold on Europe Fought 1939-1945 German offensive against Allied shipping U-boat tactics relied heavily on Enigma communication By 1941, most traffic was read by Allies


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


Bombes & Colossus: 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


Purple: 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


JN-25: 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


Pacific Theater: 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


D-Day: 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


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


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


Slide16: Thank you. Any questions?