US Navy submarines emerge, move through oceans in 1940s

During the war years, a branch of the U.S. military maintained strict secrecy, akin to avoiding publicity like Poison Ivy. This secrecy was enforced from the day of the Pearl Harbor attack until the end of the war in 1945. The Navy's submarine fleet exemplified this 'silent service' approach.

What does the phrase 'rubber stamp of top secrecy' imply about the military's operations?

Describe the significance of Pearl Harbor in relation to the military's secrecy.