Unconditional Security of a Quantum-key Storage Device

First implementations of Quantum-key Distribution Cryptosystems have shown the need to use a storage device on which to keep a copy of the key that such cryptosystems create and distribute between a pair of users. Such users must be able to access their device to take enough key to code and decode the messages they send each other over a public channel. Because of the importance of the key stored on such device, it is critical to ensure that the device could not be victim of natching attack from the public channel and that no information about the key could be stolen. This article presents a suite of three different architectures which aim is to keep such device totally safe, allowing any user to communicate safely with the other one using the key stored on it.