12 January 2001
One of the Tempest FOIA docs NSA released to Cryptome recently concerns NONSTOP, a term whose definition is classified as SECRET. About half of the document, NACSEM 5112, "NONSTOP Evaluation Techniques," has been redacted, and it will published on Cryptome soon.
From the clear text, NONSTOP appears to refer to protection against compromising emanations of cryptographic systems, and maybe in particular radio crypto systems.
Another document, NSTISSAM TEMPEST/2-95, states that NONSTOP is the primary TEMPEST vulnerability of transportable systems, aircraft and ships.
We've been unable to retrieve more than a few words from the redacted portions (by use of xerography to reveal text below the overwrites), and would appreciate any leads on what NONSTOP means. Send to: firstname.lastname@example.org
Joel McNamara has been searching for NONSTOP information for some time:
We would also like to learn more about covert surveillance by "resonance" technology. Peter Wright, ex-MI5, in his Spycatcher (1987), provides most interesting anecdotes about this. He writes of remotely "radiating" specially-designed objects in a space to pick up signals, and tells of several covert operations in which MI5 used this method.
Wright also describes the use of supersensitive microphones to pick up the daily setting of rotors on cryptomachines of the time, in particular the Hagelins made by CryptoAG.
This loops back to NONSTOP and the question of what may be the signatures and compromising emanations of today's cryptosystems which reveal information in ways that go beyond known sniffers -- indeed, that known sniffers may divertingly camouflage.
Along this line, the 1996 National Research Council CRISIS report -- which advocated loosening encryption controls -- to address FBI opposition, recommended increased funding for other surveillance technologies to counter encryption that have never been identified, although Carnivore may be one such, along with keyboard sniffers and who knows what else that has been passed to domestic law enforcement by the intelligence agencies to crack crypto protection.