A method and device for realizing A2 Trojan detection by compatible fault scanning test

Abstract

The invention discloses a method and device for realizing A2 Trojan horse detection through compatible fault scanning test, and the method comprises the following steps of S1, inserting a multifunctional controller and more than one composite ring oscillator in a gate-level netlist generation stage of a chip to be tested, and controlling the working mode of each composite ring oscillator by the multifunctional controller; S2, executing a fault test on the chip to be tested, and configuring a multifunctional controller to enable the working modes of the composite ring oscillators to alternatelychange at a scanning shift stage to enhance the hopping of the suspicious signals, or enable the composite ring oscillators to be in an oscillation state within a specified duration of a response capture stage, and detect an A2 Trojan horse during a fault test execution process. The method and the device have the advantages that the implementation method is simple, the area cost is small, the detection efficiency is high, and the A2 Trojan horse can be detected at the early stage of the fault test, etc.

Description

technical field [0001] The invention relates to the technical field of hardware Trojan horse detection, in particular to a method for realizing A2 Trojan horse detection through a compatible fault scanning test. Background technique [0002] During the manufacturing process of chips, Trojan implanters may use the processing process to implant hardware Trojans on chips, and the implantation of hardware Trojans will cause immeasurable consequences. Therefore, it is necessary to detect hardware Trojans on chips. According to the working mode of the hardware Trojan trigger circuit, the hardware Trojan can be divided into digital logic trigger type and analog circuit trigger type, among which A2 type trigger is a typical analog circuit trigger, and Trojan horses triggered by A2 type are collectively referred to as A2 Trojan horse. The trigger circuit of A2 type trigger is as figure 1 As shown, M0 can be regarded as a low-level open switch, M1 can be regarded as a high-level open...

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Problems solved by technology

[0008] 2. If there are multiple suspicious signals that need to be monitored, it is necessary to design a dedicated timer and counter for each suspicious signal. Generally, there are multiple suspicious signals in the original chip that may be used as A2 Trojan trigger inputs, and a large number of suspicious signals need to be set. Timers and counters with large area overhead;

[0009] However, if the method of shared timing is considered, that is, let n suspicious signals share one time window, although n-1 timers can be saved, but the n signals can only be set with one time window length, which will reduce the detection flexibility , if each suspicious signal occupies a dedicated counter, such as Figure 5 As shown in (a), the area overhead of this type of method is still relatively large;

[0010] If the time-sharing counting method is adopted, that is, the method of inserting a multiplexer is adopted, and only the selected signal is monitored in each time window. Although the number of counters can be saved, this type of method may cause the multiplexer to be just Suspicious signals that are frequently jumping are not selected, and the jumps of unselected suspicious signals are missed, so that the triggering of the A2 Trojan horse cannot be monitored, such as Figure 5 as shown in (b)

[0011] 3. For each suspicious signal, the statistical characteristics of its jumps are different under different applications, so it is difficult to set a reasonable time window length and jump times threshold. If the time length is too short or the number of jumps is too small, normal The application may be frequently interrupted, and if the time length is too long or the number of jumps is too large, even if the A2 Trojan has been triggered, the frequency jump confirmation signal cannot be set to "1", resulting in failure to play the role of monitoring and alarming

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