Quantum Cryptography: From Theory to Implementation Olivier Guerreau ECE Georgia Tech Quantum cryptography has become today a working application of quantum information processing. Since the first Quantum Key Distribution (QKD) protocol introduced by Bennett and Brassard in 1984, many encoding techniques have been presented with photons and implemented over optical fiber or free space to enable secure key transmission. The scheme developed at the Georgia Tech Lorraine laboratory uses photon phase encoding over 1.55um fibers and allows shoe box size implementation for potential commercial applications."