Re: What have we done? (Here's what.)

Ethan M. O'Connor (zudark@mit.edu)
Sat, 21 Jun 1997 15:34:05 -0400


At 12:14 PM 6/21/97 -0700, Karl J. Runge wrote:
>So... the Ultimate Code Breaking computer would be every atom in the Universe
>trying a key each electron orbit. (I gotta get me one of those!)
>
>How many keys could it check in, say, 10 billion years (the estimated
>age of the universe), which is about 10^10 * 10^7 = 10^17 seconds?
>
>Number of keys = (number of computers)
> * (keys per second for one computer)
> * (number of seconds)
>
>Number of keys = 10^80
> * 10^15
> * 10^17
>
> = 10^112 = 2^372
>
>So a 372 bit key is REALLY safe IMHO against brute force attack!
>
>This is basically just doing Triple-DES twice, which I imagine
>is barely noticeable performance-wise when encrypting/decrypting
>messages.
>
>
>Karl

However, the idea behind quantum computing doesn't really lend
itself to that kind of calculation... a quantum computer would
more or less try all of the keys simultaneously and settle into
a quantum state "representing" the solution. The hard part
is setting the system up correctly ;)

Of course, it's really only large number factoring for which the
precedures for Quantum calculations have been rigorously defined,
so this may not even apply to DES...

-ethan

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