1. PURPLE and The Life of William Friedman Peter Smith Matt Salmon

2. PURPLE  A Japanese cryptographic machine used before and during WWII  Similar to the German Enigma  Broken by William Friedman  MAGIC- information gained from decryptions (ULTRA in WWII) Photo courtesy of: http://en.wikipedia.org/wiki/PURPLE

3. How it Works  Used an electromechanical stepping-switch system  Plugboard and four coding wheels  Divided Alphabet: –“Twenties”- twenty consonants –“Sixes”- six vowels –Used a different algorithm to encipher the two groups  “Twenties” enciphered on three stepping switches –Fast, medium and slow –Repetition = 25x25x25 = 15,625  “Sixes” enciphered on one six level, twenty-five position stepping switch –Repetition = 25

4. Photo courtesy of: http://frode.home.cern.ch/frode/crypto/simula/purple/operation.html

5. William Friedman  Born in 1891 in Kishinev Bessarabia  Childhood  Family  Education  Adult life and work in cryptology  Considered worlds greatest cryptologist Photo courtesy of: http://en.wikipedia.org/wiki/William_F._Friedman

6. Early Life  Life at Riverbank –Influenced by Elizabeth Gallup’s work –George Fabyan  Accomplishments –Index of Coincidence –Joint success with wife –SIGABA Machine (with Rowlett)  American Black Chamber –Signals Intelligence Service (SIS)

7. Friedman and PURPLE  Similar to breaking the ENIGMA –Cribs –Errors by senders  Friedman and Rowlett –Japanese abolished previous codes and methods  1940: Construction of a “duplicate” of PURPLE  Francis A. Raven –Discovered key to keys Frank Rowlett Photo courtesy of: http://www.fas.org/irp/agency/inscom/journal/98-oct-dec/article6.html

8. Friedman after PURPLE  Armed Forces Security Agency  National Security Agency (NSA)  Retirement: –The Shakespearean Ciphers Examined – Health problems –Military Intelligence Hall of Fame posthumously

9. MAGIC  Information gained from PURPLE interceptions  Limited number of people eligible to see MAGIC  Fear of possible leak of information

10. PURPLE’s Impact in WWII  Pearl Harbor –Warning signs –Intercepted messages  http://ibiblio.org/pha/timeline/411201e.html http://ibiblio.org/pha/timeline/411201e.html  http://ibiblio.org/pha/timeline/411202e.html http://ibiblio.org/pha/timeline/411202e.html  http://ibiblio.org/pha/timeline/411207b.html http://ibiblio.org/pha/timeline/411207b.html  http://ibiblio.org/pha/timeline/411206d.html http://ibiblio.org/pha/timeline/411206d.html

11. Other Impacts  D-Day –Known location of German troops –Further confirmed trick worked  Japanese Evacuation –Executive Order No. 9066 –President Roosevelt  American advantage in WWII –Outcome  Questions?