Move Over, Quantum Cryptography: Classical Physics Can Be Unbreakable Too 126
MrSeb writes "Researchers from Texas A&M University claim to have pioneered unbreakable cryptography based on the laws of thermodynamics; classical physics, rather than quantum. In theory, quantum crypto (based on the laws of quantum mechanics) can guarantee the complete secrecy of transmitted messages: To spy upon a quantum-encrypted message would irrevocably change the content of the message, thus making the messages unbreakable. In practice, though, while the communication of the quantum-encrypted messages is secure, the machines on either end of the link can never be guaranteed to be flawless. According to Laszlo Kish and his team from Texas A&M, however, there is a way to build a completely secure end-to-end system — but instead of using quantum mechanics, you have to use classical physics: the second law of thermodynamics, to be exact. Kish's system is made up of a wire (the communication channel), and two resistors on each end (one representing binary 0, the other binary 1). Attached to the wire is a power source that has been treated with Johnson-Nyquist noise (thermal noise). Johnson noise is often the basis for creating random numbers with computer hardware."
Unbreakable encryption is easy! (Score:5, Insightful)
Re:unbreakable been around for a while (Score:5, Insightful)
It's been proposed, and it won't work. (Score:5, Insightful)
As someone pointed out, this was on Slashdot 7 years ago. Here's the referenced paper. [arxiv.org]
The idea is simple. At both ends of the wire, random data modulated with content is being emitted. At any point on the wire, you see the sum of two random sources. But each end knows their own random data, and can subtract it out.
To break the system, you need two taps on the wire, some distance apart. Now you get to see the sums of the signals from each end, but with different time shifts between them due to propagation delay. With that data, you can separate out what's coming from each end. This allows recovering the original signals.
"No new encryption system is worth looking at unless it comes from someone who has already broken a very hard one." - Friedman.
Re:The fundamental idea (Score:4, Insightful)