Drexel University

Vaibhav Venugopal Rao

Ioannis Savidis

Kyle Juretus

The transition to a horizontal integrated circuit (IC) design flow has raised concerns regarding the security and protection of IC intellectual property (IP). Obfuscation of an IC has been explored as a potential methodology to protect IP in both the digital and analog domains in isolation. However, novel methods are required for analog mixed-signal circuits that both enhance the current disjoint implementations of analog and digital security measures and prevent an independent adversarial attack of each domain. A methodology generates functional and behavioral dependencies between the analog and digital domains that results in an increase in the adversarial key search space. The dependencies between the analog and digital keys result in a 3&#xd7; increase in the number of iterations required to complete the SAT attack.

Securing analog mixed-signal integrated circuits through shared dependencies

An approach is described for enhancing the security of analog circuits using Satisfiability Modulo Theory (SMT) based design space exploration. The technique takes as inputs generic circuit equations and performance constraints and, by exhaustively exploring the design space, outputs transistor sizes that satisfy the given constraints. The analog satisfiability (aSAT) methodology is applied to parameter biasing obfuscation, where the width of a transistor is obfuscated to mask circuit properties, while also limiting the number of keys that produce the target performance requirements.

Transistor sizing for parameter obfuscation of analog circuits

A key based technique that targets obfuscation of critical circuit parameters of an analog circuit block by masking physical characteristics of a transistor (width and length) and the circuit parameters reliant upon these physical characteristics (i.e. circuit biasing conditions, phase noise profile, bandwidth, gain, noise figure, operating frequency, etc.). The proposed key based obfuscation technique targets the physical dimensions of the transistors used to set the optimal biasing conditions. The widths and/or lengths of a transistor are obfuscated and, based on an applied key sequence, provides a range of potential biasing points. Only when the correct key sequence is applied and certain transistor(s) are active, are the correct biasing conditions at the target node set.

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Philadelphia, PA, United States of America

Vaibhav Venugopal Rao