| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent counterfeiting or unauthorized copying of a card, using a principle that the observation of a memorized quantum state changes the quantum state. <P>SOLUTION: The security device comprises a quantum memory 101 for storing a quantum state, a quantum state generating unit 102 for generating the quantum state from inputted information, an information entry unitary transformation unit 103 for conducting unitary transformation for the quantum state, a memory 104 for holding quantum information parameters indicative of the generation process of the quantum state, an information output unit 105 for conducting interaction between the quantum state and an auxiliary quantum state and measuring the quantum memory in which the auxiliary quantum state contained in the result of calculation for unitary transformation is stored to output information from the quantum state, and a quantum state validation unit 106 for measuring an unauthorized access to quantum state using an identity operator. Consequently, if information is accessed illegally, focusing of a wave bundle occurs. Accordingly, traces can be left at the quantum state, and unauthorized access can be detected. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
