Related Clues:

• Ultra-secret org.
• W.W. II spy grp.
• Gives a thumbs-up
• Hush-hush grp.
• 'The Puzzle Palace' grp.
• Spy org. created by FDR
• Code-cracking org.
• Codebreakers' org.
• CIA predecessor
• Decryption org.
• Old spy grp.
• CIA's forerunner
• Hush-hush W.W. II agcy.
• Fed. hush-hush group
• Govt. code crackers