The paper by Frédéric Grosshans and Philippe Grangier proposes several methods for quantum key distribution (QKD) using random distributions of coherent or squeezed states, demonstrating their security against individual eavesdropping attacks. These protocols require a transmission line between Alice and Bob to be larger than 50%, but they do not rely on "non-classical" features like squeezing. The security of these protocols is based on the no-cloning theorem, which limits the signal-to-noise ratio of possible quantum measurements. The approach can also be applied to evaluate other QKD protocols using Gaussian statistics, such as squeezed or EPR beams. The authors show that the security of these protocols is independent of the quantum features of the beam, such as squeezing or entanglement, and can be achieved with coherent states. The paper includes a detailed analysis of the protocol's security, including the Shannon formula for the optimum information rate and the sliced reconciliation protocol for errorless bit string transformation. The results demonstrate that these protocols can achieve a secret key rate that is asymptotically secure for losses smaller than 3 dB or a teleportation fidelity larger than 2/3.The paper by Frédéric Grosshans and Philippe Grangier proposes several methods for quantum key distribution (QKD) using random distributions of coherent or squeezed states, demonstrating their security against individual eavesdropping attacks. These protocols require a transmission line between Alice and Bob to be larger than 50%, but they do not rely on "non-classical" features like squeezing. The security of these protocols is based on the no-cloning theorem, which limits the signal-to-noise ratio of possible quantum measurements. The approach can also be applied to evaluate other QKD protocols using Gaussian statistics, such as squeezed or EPR beams. The authors show that the security of these protocols is independent of the quantum features of the beam, such as squeezing or entanglement, and can be achieved with coherent states. The paper includes a detailed analysis of the protocol's security, including the Shannon formula for the optimum information rate and the sliced reconciliation protocol for errorless bit string transformation. The results demonstrate that these protocols can achieve a secret key rate that is asymptotically secure for losses smaller than 3 dB or a teleportation fidelity larger than 2/3.