A quantum leap: Researchers create super-secure computer network Seungjai Min Hansang Bae Hwanjo Heo

Quantum Cryptography? Uses light particles, photons through optical fiber instead of electric waves on wire A defining discovery in physics: that subatomic particles can exist in multiple states at once until something interacts with them. Eavesdropping on the photons, such as setting up a photo detector to read the code, makes the codes unusable and can be detected.

Basic Idea

Quantum Key Distribution Core aspect of quantum networking Two parties share a key obtained by QKD before data communication Separated in two channels: quantum channel and public channel Uses different polarization of a photon to encode a bit Example protocols: BB84, B92

Working Examples The Boston network(BBN – Havard – Boston university) is the first internet-integrated system. A group in Europe recently made the first quantum encrypted bank transaction. MagiQ Technologies and id Quantique are selling commercial QKD systems.

Pros & Cons Nearly Impossible to steal, even with a super- powered computer Detect if someone is listening “Secure” – randomness, no cloning Distance Limitations Availability –Expensive (MagiQ sells it at $50,000 per piece) –Vulnerable to DOS –Keys can’t keep up with data transmission

Questions?