Patent ID: 7656189

Claim:
A method for detecting an unwanted function implemented in an integrated circuit (IC), the method comprising: reading by a controller implemented on the IC at a first time while the IC is operating according to a circuit design, a first data set from a subset of memory cells that stores state information of the circuit design; wherein the subset of memory cells is specified in a memory map that indicates memory cells whose contents are not to change; determining whether the first data set is different from a second data set by the controller; and outputting, in response to the first data set being different from the second data set, a threat signal by the controller, the threat signal indicating the presence of unauthorized logic in the circuit design, wherein the determining includes: generating a first signature value as a function of data in the first data set; and comparing the first signature value to a second signature value representative of data in the second data set; wherein the first signature value being different from the second signature value indicates that the first data set is different from the second data set.