| 摘要 |
PURPOSE: To provide a locked key collation circuit whose safety degree is guaranteed by constituting the circuit in such a way that it cannot be accessed from an external part after data is written into an internal memory being the object of secrecy. CONSTITUTION: The locked key collation circuit is provided in an IC package 100. Peculiar random signal patterns emitted from an internal circuit 1 in the IC package 100 are set to be locked key signals, the locked key signals written into the internal memory 2 are transferred to a register 4 and the locked key signals transferred to the register 4 are collated with the locked key signals from the internal circuit 1 in a coincidence collation circuit 5. The coincidence collation circuit 5 outputs the signals to the gate 3, continues closing, sets the gate 3 to a deadlock state and denies access from the external part hereafter as long as the signals are matched. |
