Quantum memories are devices where one can store and retrieve quantum states. In order to preserve the states in the presence of decoherence, one may use quantum error correction techniques. An alternative approach consists of employing interacting spins so that no active action on the memory is required during the whole storage period. In this talk I will analyze the robustness of such memories against decoherence, as well as those based on dissipation, whereby an interaction of the spins with an environment is properly engineered. I will also analyze the security of protocols using quantum memories, like those related to quantum money and credit cards, as well as some experimental attempts to extend the memory time of qubits at room temperature.