Slashdot Mirror
Move Over, Quantum Cryptography: Classical Physics Can Be Unbreakable Too
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."
The important point that people seem to be missing is that quantum encryption *is* one-time pad. The system of quantum encryption consists of using entangled particles to be the shared source of randomness. Because both parties would be aware if anyone besides the two of them were observing the shared randomness, they can't exactly communicate via entanglement, but they can reach an arbitrary (ie. not decided by either of them) consensus on the values in a random stream. This random stream is then used as the key of a one-time-pad where the ciphertext is transported over a traditional channel of communication.
For this reason, I consider the term "quantum encryption" to be a bit of a misnomer - nothing about the actual en/de cryption is quantum. A better name would be "quantum key distribution" or "quantum consensus generation"