Quantifying how much quantum information can be eavesdropped

Summary The most basic type of quantum information processing is quantum entanglement. In a new study published in EPJ B, Zhaonan Zhang from Shaanxi Normal University, Xi'an, China, and colleagues have provided a much finer characterisation of the distributions of entanglement in multi-qubit systems than previously available. These findings can be used in quantum cryptography to estimate the quantity of information an eavesdropper can capture regarding the secret encryption key.