ULTRA in the Atlantic:
German Naval Communications Intelligence
SRH-024national security agency
central security service
Table of Contents
Chapter Page I Organization and Working of German Naval Communications Intelligence 1 II Intelligence Disseminated to U-boats and the Sources Acknowledged in U-boats Traffic 11 III German Intelligence on Allied Convoys in the Atlantic 21 IV Compromise of Naval Ciphers #3 and #4 35 V "B-Dienst" Aboard U-boats 55 VI German-Japanese Cooperation in Communication Intelligence 65 VII German Fears of the Compromise of Their Naval Cipher 83