united states cryptologic history
 
  Pearl Harbor Revisited:
  United States Navy
Communications Intelligence, 1924-1941
 
   
CH-E32-94-01
national security agency
central security service


UNITED STATES CRYPTOLOGIC HISTORY

Pearl Harbor Revisited:
United States Navy Communications Intelligence
1924-1941

Frederick D. Parker

CENTER FOR CRYPTOLOGIC HISTORY
NATIONAL SECURITY AGENCY
1994


Table of Contents

    Introduction

    Earliest Efforts
    Role of ONI
    Early War Plans
    Japanese Fleet Capabilities and Intentions
    Cryptologic Challenge: Navy-Army Cooperation
    Bureaucracy Prevails
    Status Quo in the Pacific
    A New Attempt at Cooperation
    Japanese Cryptography
    Recovering the "Blue Book"
    Introducing JN-125
    Turning Victory into Defeat
    Introducing "Purple"
    Disarmament: Paying the Price
    Confusing Diplomacy
    Struggling for Resources
    Planning for War
    War Games
    Pacific Buildup
    National Emergency
    Circumstances Favor Diplomatic Targets
    Information Gaps
    Cooperation with Allies
    The Move to Hawaii
    Support to the Pacific Fleet
    Japanese Intentions Revealed
    Support to the Asiatic Fleet
    Japanese Strategy
    Japanese Navy
    Diplomatic Messages
    Warning Messages
    Reaction
    Comint After the Opening Attack
    Conclusion

    Appendix A: Naval Messages Intercepted between 5 September and 4 December 1941
    Appendix B: Summary of Diplomatic Messages, July-November 1941
    Appendix C: Highlights from COM-14 Daily COMINT Summary

    Notes
    Abbreviations
    Notes on Sources
    Bibliography

iii


Last updated: November 20, 2000

Transcribed and formatted by Patrick Clancey