Origin of the nomenclature "red-black"?

[Steven M. Bellovin]

Does anyone know where and when the use of "red" (inside networks) and
"black" (outside, encrypted networks for crypto gear) started?  I'm
especially intrigued by the use of "red", since in other military
nomenclature (in the US) blue is the usual color for US and friendly
forces and red is (for obvious geopolitical reasons) the enemy.

One hypothesis I've come up with is that the color was chosen by the
British from the so-called "all-red route" -- the web of underseas
telegraph links that touched only Britain and its colonies.  It was
named for the usual map color of the time (~100 years ago) for the
British empire.  The all-red route gave the British protection against
(some) foreign eavesdropping; it was also useful offensively, since the
1920 Official Secrets Act contained a provision requiring cable
companies to turn over copies of all telegrams to the government.
(Source: "The Invisible Weapon: Telecommunications and International
Politics, 1851-1945", by Daniel R. Headrick, Oxford University Press,
1991.)


		--Steve Bellovin, http://www.cs.columbia.edu/~smb

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