  Besides achieving secure communication between two spatially-separated
parties, another important issue in modern cryptography is related to secure
communication in time, i.e., the possibility to confidentially store
information on a memory for later retrieval. Here we explore this possibility
in the setting of quantum reading, which exploits quantum entanglement to
efficiently read data from a memory whereas classical strategies (e.g., based
on coherent states or their mixtures) cannot retrieve any information. From
this point of view, the technique of quantum reading can provide a new form of
technological security for data storage.
