Entangled State Quantum Cryptography: Eavesdropping on the Ekert Protocol
Entangled State Quantum Cryptography: Eavesdropping on the Ekert Protocol
Using polarization-entangled photons from spontaneous parametric down-conversion, we have implemented Ekert's quantum cryptography protocol. The near-perfect correlations of the photons allow the sharing of a secret key between two parties. The presence of an eavesdropper is continually checked by measuring Bell's inequalities. We investigated several possible eavesdropper strategies, including pseudo--quantum-nondemolition …