One of the greatest threats to security are Trojans - rougue modifications to ICs that create a latent security risk. This theat, which is very much an unspoken threat, is of great importance to chip manufacturers, software companies and systems providers. This invention detects Trojans, far faster and more accurately than existing methods. It is based on implementing test circuitry into the chip that performs compressive sensing. Doing so has negligable impace on chip performance, size, cost or power usage, but can quickly and reliabiably detect Trojans.