Quantum cryptography with continuous variables

Summary form only given. Quantum cryptography with continuous variables is an emerging field that consist in providing two communicating parties with a random secret key, using the quadrature components of electromagnetic fields as quantum carriers. According to quantum mechanics, the quantum states of the carriers used to establish the key are perturbed by the presence of unauthorized eavesdropping. Here, we present a new quantum cryptography protocol based on entangled quadratures of a two-mode electromagnetic field generated by phase sensitive parametric amplification (PSA).