A semiconductor device comprises processing logic arranged to execute program instructions. The semiconductor device further comprises signature generation logic arranged to receive at least one value from at least one internal location of the semiconductor device, and to generate a current signature value, based on the at least one received value. Validation logic is arranged to validate the current signature value generated by the signature generation logic. The processing logic is further arranged, upon execution of a signature validation instruction, to enable the validation of the current signature value provided by the validation logic.