🚀 go-pugleaf

phr@telebit.com (Paul Rubin) writes:

>   So what are some of the methods used to attack an encrypted text, when the
>   encryption method is unknown?

>One method used in WW2 was to send divers to recover encoding equipment,
>codebooks, etc. from sunken enemy ships (perhaps sometimes ships
>that were attacked specifically for the purpose of getting the
>crypto stuff).  Another method is to capture the sender or receiver
>of the messages and demand the encryption keys etc. at gunpoint.

>There are also cryptanalytic methods, but I mention the WW2 story to
>underscore the fact that sci.crypt readers responding to "challenges"
>are fortunately NOT likely to use ALL of the methods that a real world
>codebreaker would use.  Any purely cryptanalytic challenge to
>sci.crypt, in order to be fair, must provide as much info as an enemy
>spy agency would be able to obtain by hook or by crook---this includes
>a complete description of the algorithm, plus some known plaintext of
>the same nature as the challenge messages.

As I note in another message, in a "real" test, you have people exchanging
messages in the cipher. And if they aren't careful, they'll compromise
it. 

-- 
Leonard Erickson		      leonard@qiclab.scn.rain.com
CIS: [70465,203]			 70465.203@compuserve.com
FIDO:   1:105/51	 Leonard.Erickson@f51.n105.z1.fidonet.org
(The CIS & Fido addresses are preferred)