Abstract: An electronic design automation (EDA) tool for executing topological and functional checks on an electronic circuit design (ECD) includes a processor and a memory that stores the ECD, graphical rules, and filter rules for executing the checks. The processor generates a test graph based on the ECD, replaces stretchable nodes with nested networks in the test graph to generate extended graphs, and decouples real edges and functional edges of each extended graph to generate real graphs and functional graphs, respectively. Based on the graphical rules, the processor executes the topological checks on an input graph of the ECD to identify real sub-graphs from the input graph that are isomorphic to a real graph. The processor further generates functional sub-graphs by combining a functional graph with each real sub-graph, and based on the filter rules, further executes the functional checks on the functional sub-graphs to identify output graphs.

Abstract: A tamper detector has input and output pins for connection to ends of a tamper detection circuit, and a corresponding set of linear feedback shift registers (LFSRs) timed by clock signals for generating pseudo-random coded detection signals as a function of seed values and of a generator polynomial defined by feedback taps. A comparator compares signals received from the detection circuit with the coded detection signals. A multiplexer provides the coded detection signal selectively from the LFSRs to the output pin and the comparator. A controller varies the seed values for different cycles of values of the pseudo-random coded detection signals. The controller also controls the generator polynomial and a frequency of the clock signals for different cycles of values of the pseudo-random coded detection signals.

Abstract: A tamper detector has input and output pins for connection to ends of a tamper detection circuit, and a corresponding set of linear feedback shift registers (LFSRs) timed by clock signals for generating pseudo-random coded detection signals as a function of seed values and of a generator polynomial defined by feedback taps. A comparator compares signals received from the detection circuit with the coded detection signals. A multiplexer provides the coded detection signal selectively from the LFSRs to the output pin and the comparator. A controller varies the seed values for different cycles of values of the pseudo-random coded detection signals. The controller also controls the generator polynomial and a frequency of the clock signals for different cycles of values of the pseudo-random coded detection signals.