Thursday, November 09, 2006

Quantum Cryptography

Somehow, I fail to see how this quantum cryptography thingy is a big deal. Isn't it just a really good random number generator?

Warning: Ignorance Alert! This is merely my layperson understanding of how this works...
If I want to decode an encrypted message, I need three things:
  1. The encoded message.

  2. The method used to encode it.

  3. The encryption key (usually a number or a word).

Say, for example, I send a secret message to my friend Ruteger. "Meet me at Steak and Shake. You're buying." I run it through my encryption machine with the key "857312." Even if someone intercepted the message and knew my encryption method, they would still need the key. In this case, the key is rather short and a computer could guess it with trial and error.

But wait... Why not generate the number with a photon? Photons can make random numbers using SCIENCE! Now, instead of the pseudo-random number key "857312," I can now have a truly random number key: "2287937."

The amount of work done by the spy is the same. Am I missing something here? Do I have a fundamentally flawed understanding of cryptography? (likely)

2 comments:

Anonymous said...

In standard encryption you can use one method or another to intercept the key during its transport. The key cannot be encrypted. Quantum cryptography, however, relies on a key that can only be read once.

SpuneDagr said...

If it can only be read once, then how do you decrypt it on the other end?