METHOD, CIRCUIT AND DEVICE FOR ENCRYPTING INTEGRATED CIRCUIT OF SINGLE CHIP MICROCOMPUTER

摘要

A method, circuit and device for encrypting an integrated circuit of a single chip microcomputer, which are applicable to the protection of programs in an integrated circuit (IC) of a single chip microcomputer. By virtue of the fact that different batches of ICs have different internal resistors, a capacitor is externally connected to an IO port on the integrated circuit, so that the internal resistor of the IO port and the external capacitor constitute an RC charge-discharge circuit. A normal working range of an RC charge-discharge parameter is preset in a program, and after the program is injected into the IC, the working range is fixed; and when each batch of ICs are delivered, they can work normally by adjusting the value of the external capacitor to enable the RC charge-discharge parameter to be in the normal range. If someone maliciously steals a program code and inputs the same into the IC, as the entry mode for RC charge-discharge parameter adjustment and the normal parameter range cannot be learnt, the lock of encryption cannot be unlocked, so that the IC finds an error when performing automatic identification, to lock the IC, so as to achieve the purpose of protecting the rights and interests of a program development owner.