[sci.crypt] One time pads

franka@mmintl.UUCP (02/05/87)

In article <12414@sun.uucp> falk@sun.UUCP (Ed Falk) writes:
>In article <9112@duke.duke.UUCP> srt@duke.UUCP (Stephen R. Tate) writes:
>>Now here's an interesting point.  The exact same amount of information has to
>>be transmitted as "key" information as will be transmitted as data. ...  So
>>what is the point of encryption at all in this case?
>
>That's the main problem with one time pads.  Their only real use is that
>you can use a slow courier ahead of time, and then use an insecure but
>fast channel (such as radio) at a later time.

A theoretical case where they would also be useful would be where you have a
secure channel from point A to point B, but no secure channel from point B
to point A.  Then you send the key information by the secure channel, and
use it for transmissions back to point A.  I can't think of any actual
instances where this would apply, though.

Frank Adams                           ihnp4!philabs!pwa-b!mmintl!franka
Ashton-Tate          52 Oakland Ave North         E. Hartford, CT 06108