Smart card safety protection circuit and smart card safety protection method

Abstract

The invention discloses a smart card safety protection method. The method is used for monitoring a running order rule of a CPU (Central Processing Unit) in real time in a time-sharing and distributed manner, and detecting whether the running of the CPU meets the running order rule; once the error of the program running order is detected, the program with error is stopped, and a chip is trigged to deal with the exception so as to ensure the execution of the program according to the correct running order and prevent program fleet; and effective safety protection is provided when the chip of the smart card is influenced by external attacks or the runtime environment is unsteady. The invention also discloses a circuit for realizing the method. The circuit comprises a current instruction code register (20), a jumping destination address register (16), a PC (Personal Computer) register (14), a PC-PRO register (22), an adding device (24), a comparator (15), a comparator (17), a comparator (26), a comparator (21), a monitoring circuit 1 (38) and a monitoring circuit 2 (39). The circuit monitors the running order of the CPU by the monitoring circuit 1 and the monitoring circuit 2, and if the CPU runs exceptionally, the circuit triggers the chip of the smart card at different time to deal with the exception so as to prevent the chip from exception.

Description

technical field [0001] The invention is mainly applied to the design field of safety micro-controller chips represented by smart cards, which can effectively improve resistance to external interference attacks and enhance the stability and reliability of chip work. Background technique [0002] In recent years, security microcontrollers represented by smart cards have been widely used in social life. As the carrier of system security and key data, smart cards are often used in fields such as identity authentication, transportation, telecommunications, and financial payment. [0003] Driven by interests, smart cards are faced with more and more various attack methods, among which interference injection attack is a common attack method, such as power interference, optical interference, pulse interference, etc. The operation of the central processing unit (CPU) is abnormal, and the so-called runaway phenomenon occurs, which causes the CPU to deviate from the normal program ope...

AI Technical Summary

Problems solved by technology

[0003] Driven by interests, smart cards are faced with more and more various attack methods, among which interference injection attack is a common attack method, such as power interference, optical interference, pulse interference, etc. The operation of the central processing unit (CPU) is abnormal, and the so-called runaway phenomenon occurs, which causes the CPU to deviate from the normal program operation. For example, the application process that has not passed the certification directly rewrites the stored data, and the record stored in the card is incorrectly changed.

In addition, the working environment of the smart card is unstable or the operation is not standardized (hot plugging, etc.) will also cause abnormal CPU operation

[0004] To protect against such problems, the general practice is to use various sensors to detect the working environment of the chip, including voltage detection, temperature detection, burr detection, light detection, etc. Once an abnormality is found, the chip is reset to prevent The chip is misoperated again, but there are problems with the response time, detection accuracy and range of these sensors, and the protection effect is not particularly ideal

In particular, these sensors are generally implemented by analog circuits, which occupy a large chip area. The obvious circuit structure can be distinguished from the physical layout. Attackers can bypass these sensors through FIB and other means, resulting in the failure of security protection.

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