🚀 go-pugleaf

This posting was sent out in RISKS-13.88 in the comp.risks.
It should be of interest here too.

-Peter

 

>1) Can you trust the criminals to provide the keys to their data and to use
>   those keys (and no others) when transmitting incriminating data?  If not,
>   what's the point?

Actually, my favorite solution to this criminal problem is to use
a one-time pad. Then it is possible to come up with two keys. One
that decrypts the conversation into a benign one and one that decrypts
it into the real message.

For instance:

Message:   P  L  U  T  O  N  I  U  M  R  E  A  D  Y

Key # 1:   1  4 10  5  7  8 12 19  4  3 10 19 21 10

Crypttext: Q  P  E  Y  V  V  U  N  Q  U  O  T  Y  I

Key # 2:  10 24  0 24  2 19 13 25 14  6  3 19  5  4

Message 2: G  R  E  A  T  C  H  O  C  O  L  A  T  E  

So the criminals send key #1 to their cohorts and register
key # 2 with the Federal Key Exchange Registry. When
the cops bug the line all they hear about is the stories
about their trip to Hershey PA. 

Of course non-one-time-pad systems can't work this way.
DES can't be rigged this way.


-Peter Wayner