| 摘要 |
PROBLEM TO BE SOLVED: To make the illegal analysis of the operation of a logic circuit to be difficult and to apply the method of illegal analysis to a general logic circuit by changing the inner logic constitution of the logic circuit, in accordance with the outer control signal of a prescribed logic circuit. SOLUTION: A logic circuit 101 has logic gates G1,..., G4, G10, and G11, EXNOR gates G5,..., G9 and a NOT gate G12. The logic gates G1,..., and G4 are the logic gates, which can switch a two input NAND function and a two input NOR function by a control signal C. The logic gates G10 and G11 are the logic gates, which can switch a two input EXNOR function and a two input EXOR function by the control signal C. When the switching of the logic constitution is controlled, based on the control signal C of random numbers synchronized with input signals A1, A2 and Ci, an inner node signal can be changed at random. |
