Cable Colors

Steven M. Bellovin smb at
Tue Jun 17 02:28:24 UTC 2008

On Mon, 16 Jun 2008 20:32:15 -0500 (CDT)
Gadi Evron <ge at> wrote:

> In one organization red was for the sensitive private network, and in 
> another red meant "danger Will Robinson", public unsafe network. In
> yet another red was for grounded power.
Right.  The universal convention in NSA-type crypto gear is
red==cleartext, black==ciphertext.  Designs have to provide proper
"red/black separation".  But when Bill Cheswick and I put in the Bell
Labs firewall in the early 1990s, we used red cables for the dangerous
outside net.

		--Steve Bellovin,

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