A Dual-Mode Successive Approximation Register Analog To Digital Converter To Detect Malicious Off-Chip Power Noise Measurement Attacks

An on-chip noise monitor using a dual-mode analog to digital converter (ADC) is developed to detect the insertion of off-chip components as malicious attempts of power noise measurement attacks. A two-step sampling scheme selecting either synchronous or asynchronous clocking enables both real-time monitoring and high-resolution diagnosis of power supply noise, respectively. The monitor detects the change in power-line impedance and assumes the happening of physical contacts by an attacker's device. A wide-band ADC with the bandwidth of 1 GHz facilitates the analysis of on-chip captured waveforms and the recognition of potentially inserted devices. Fabricated in 65 nm CMOS, the on-chip noise monitor is examined for the detectability of series resistors as well as parallel capacitors that are intentionally inserted on power lines. The experiments demonstrated the detection of a power current sensor in series to power lines, and also the attachment of an oscilloscope probe, through the analysis of on-chip captured power noise waveforms.