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?