[Milsurplus] [ARC5] Dead Pigeons, Secret Messages, and Random Numbers

[Mike A]

On Tue, Nov 27, 2012 at 11:22:05AM -0800, J. Forster wrote:
> I suppose it's possible to built something like an Enigma, with several
> rotors, wired randomly, that went into a thing like a Veeder-Root counter.
> 
> The last rotor would have 26 (or 36) output lines. The single active one
> would print it's letter, and then the rotor would advance.
> 
> Such a thing would not be truly random, but would probably be good enough
> for shortish messages.
> 
> Maybe that'd work.
> 
> It still begs the question, what did they actually do.

Yes, it does, and I doubt anyone inside who knows will ever tell just how
key material is made. Once you have some notion of how the key material
is generated, you have a potential opening wedge into cryptanalysis of
things sent on machines using that key material.

I conjecture that key material generation involves noise generators using
gas tubes, Zener diodes forward-biased into their "knee" regions, and very
probably things I haven't even thought of in 40 years of working with this
stuff. I can talk about it precisely because I'm not on the inside and I don't
know.

According to David Kahn, the FBI (or NSA) determined from letter frequencies
in VENONA evidence that the one-time pads found during the investigation of
the case had been hand-typed by person or persons hitting typewriter number
keys "randomly". There was a definite, though slight bias, towards certain
areas of the keyboard. That wasn't good enough, by itself, to get very far
into breaking the messages that were found or intercepted, and most VENONA
messages still haven't been penetrated at all. Most entries into VENONA were
made because the Soviets inexplicably -- and fatally -- *RE-USED* pages of
one-time pads. Even though the cipher text was superenciphered by additive
tables, once the superencipherment was stripped, the re-use became evident,
and something like 49% of VENONA messages were broken (except for codenames
referring to people, places, tasks, etc.) in 1944.

-- 
Mike Andrews, W5EGO
mikea at mikea.ath.cx
Tired old sysadmin