Hackers attempt to gain access to cryptographic integrated circuits, such as smart card controllers, in an effort to steal valuable user data, passwords, and the like. One technique hackers use is to inject electrical faults to cause circuits to malfunction in ways that give the hackers access to the memory and other resources of the integrated circuit. Fault injections are a serious threat against secure circuits. There are multiple methods utilized to inject faults within cryptographic circuits. Among the methods are laser, voltage, and electromagnetic (EM) fault injection. Laser fault injection is a popular method due to its high spatial and temporal resolutions. However, the use of laser for fault injection has limitations. An increased number of metal layers for routing signals in a chip, as well as progressive countermeasures increase the inefficiency of laser attacks. Voltage spike injection is also utilized by injecting a voltage spike directly into a substrate of a targeted integrated circuit. Voltage spike injection produces ground bounces or voltage drops with respect to the intensity of the spike. EM fault injection via a targeted electromagnetic pulse is more commonly being utilized for targeted attacks that aim to disrupt logic circuit behavior within integrated circuits.
Two types of EM injection platforms are known to be mounted to induce faults into circuits. The Harmonic EM injection platform produces sine EM waves that can be modulated to produce faults. Harmonic EM injections may disturb the behavior of an internal clock of an integrated circuit, as well as bias a true random number generator. Additionally, EM Pulse (EMP) injection, produced with a high voltage pulse generator and an injector, has been shown to create faults exploitable from a cryptanalysis point of view. EMP injection produces a single but powerful EMP at a desired time and location on a targeted integrated circuit that creates a sudden current flow in the power ground networks of the targeted integrated circuit, thereby creating voltage drops, ground bounces, and timing faults. Each of these forms of fault injection is difficult to defend against. As devices become smaller and more pervasive in our environment, the susceptibility to security breach becomes increasingly more important and more difficult to counter.
In the following description, the use of the same reference numerals in different drawings indicates similar or identical items. Unless otherwise noted, the word “coupled” and its associated verb forms include both direct connection and indirect electrical connection by means known in the art, and unless otherwise noted any description of direct connection implies alternate embodiments using suitable forms of indirect electrical connection as well.