Down-conversion time-sharing A2 Trojan horse detection method and device based on composite ring oscillator

Abstract

The invention discloses a down-conversion time-sharing A2 Trojan horse detection method and device based on a composite ring oscillator. The down-conversion time-sharing A2 Trojan horse detection method comprises the following steps: 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, wherein the composite ring oscillator is obtained by sequentially connecting a chain head control unit and a plurality of chain internal rendering units into an end-to-end ring chain structure, and the multifunctional controller controls the working mode of the composite ring oscillator. S2, during detection, controlling the composite ring oscillator to alternately work in a normal function mode and an oscillation mode so as to activate the implanted A2 Trojan horse; and S3, judging the operation result of the chip to be tested when the operation of the test program is finished, and judging that the chip tobe tested is possibly implanted with the A2 Trojan horse if the expected function is not achieved. The down-conversion time-sharing A2 Trojan horse detection method has the advantages of being simplein implementation method, high in detection precision and efficiency, high in flexibility and the like.

Description

technical field [0001] The invention relates to the technical field of hardware Trojan detection, in particular to a method and device for detecting a down-frequency and time-division A2 Trojan based on a composite ring oscillator. 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 ...

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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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