Security Bounds for Continuous Variables Quantum Key Distribution

Quantum cryptography, that is, quantum key distribution (QKD) followed by one-time pad, allows two honest parties to interchange private information in a completely secure way. Quantum states sent through an insecure channel are used to establish correlations between the sender, Alice, and the receiver, Bob. Since the channel is not secure, the eavesdropper, Eve, can interact with the sent states. However, the no-cloning theorem [1] limits her action: she cannot produce and keep a perfect copy of the intercepted quantum state. After this correlation distribution, Alice and Bob employ reconciliation techniques in order to distill from their list of classical symbols perfectly correlated and completely random bits about which Eve has no information, that is, a secret key. This key is later consumed for sending private information by means of the