Srinivas Devadas

Bio: Srinivas Devadas is an academic researcher from Massachusetts Institute of Technology. The author has contributed to research in topics: Sequential logic & Combinational logic. The author has an hindex of 88, co-authored 480 publications receiving 31897 citations. Previous affiliations of Srinivas Devadas include University of California, Berkeley & Cornell University.

Verification of asynchronous interface circuits with bounded wire delays

Abstract: We address the problem of verifying that the gate-level implementation of an asynchronous circuit, with given or extracted bounds on wire and gate delays, is equivalent to a specification of the asynchronous circuit behavior described as a classical flow table. We give a procedure to extract the complete set of possible flow tables from a gate-level description of an asynchronous circuit under the bounded wire delay model. Given an extracted flow table and the initial flow table specification, we give procedures to construct a product flow table so as to check for machine equivalence under various modes of operation.

Gate-Delay-Fault Testability Properties of Multiplexor-Based Networks

Abstract: We investigate the gate-delay-fault testability properties of multilevel, multiplexor-based logic circuits. Based on this investigation, we describe a procedure for synthesizing gate-delay-fault testable multilevel circuits. The procedure involves the construction of a multilevel circuit from a general, unordered Binary Decision Diagram (BDD) by replacing vertices of the BDD with multiplexors. The procedure relies on the following result derived in this article: If the multilevel circuit constructed from the BDD is initially fully single stuck-at fault testable, or made fully single stuck-at fault testable by redundancy removal, then it is completely robustly gate-delay-fault testable. Once the initial gate-delay-fault testable circuit has been obtained, constrained algebraic factorization is used to improve the area and performance characteristics without compromising testability. Unlike previous techniques for synthesizing robustly gate-delay-fault testable circuits, this procedure can be used to synthesize fully testable circuits directly from nonflattenable, logic-level implementations.

Diastolic arrays: throughput-driven reconfigurable computing

Abstract: Diastolic arrays are arrays of processing elements that communicate exclusively through First-In First-Out (FIFO) queues. FIFO virtualization units enable relaxed timing of data transfers, and include hardware support to guarantee bandwidth and buffer space for all data transfers, which may follow composite paths through the network. We show that the architecture of diastolic arrays enables efficient synthesis from high-level specifications of communicating finite state machines so average throughput is maximized. Preliminary results are presented on an H.264 decoding benchmark.

Signal generator based device security

Abstract: Subsets of multiple signal generator circuits embodied in a device are selected, and then a volatile value for the device is generated from the selected subsets. The volatile value may be used for authentication of the device and/or for cryptographic procedures performed on the device. The signal generator circuits may each comprise an oscillator circuit, and the selection of the subsets may be according to a comparison of the outputs of the subsets of circuits, for example, according to a comparison of output oscillation frequencies.

Security and Reliability Properties of Syndrome Coding Techniques Used in PUF Key Generation

Abstract: A Physical Unclonable Function (PUF) uniquely identifies identically manufactured silicon devices. To derive keys, a stability algorithm is required. Unlike conventional error correction used in communication systems, a PUF stability algorithm has a dual mandate of accounting for environmental noise while minimally disclosing keying material; the latter, security, aspect is generally not a concern for conventional error correction use cases. For the purpose of comparison, we classify PUF stability algorithms into three Syndrome coding methods: Code-Offset; Index-Based Syndrome; Pattern Vector. We analyze and compare these methods with a focus on security and reliability properties, including a comparison of relevant security assumptions as well as a comparison of relevant ASIC PUF reliability data.

TaintDroid: An Information-Flow Tracking System for Realtime Privacy Monitoring on Smartphones

Abstract: Today’s smartphone operating systems frequently fail to provide users with visibility into how third-party applications collect and share their private data. We address these shortcomings with TaintDroid, an efficient, system-wide dynamic taint tracking and analysis system capable of simultaneously tracking multiple sources of sensitive data. TaintDroid enables realtime analysis by leveraging Android’s virtualized execution environment. TaintDroid incurs only 32p performance overhead on a CPU-bound microbenchmark and imposes negligible overhead on interactive third-party applications. Using TaintDroid to monitor the behavior of 30 popular third-party Android applications, in our 2010 study we found 20 applications potentially misused users’ private information; so did a similar fraction of the tested applications in our 2012 study. Monitoring the flow of privacy-sensitive data with TaintDroid provides valuable input for smartphone users and security service firms seeking to identify misbehaving applications.

TaintDroid: an information-flow tracking system for realtime privacy monitoring on smartphones

Abstract: Today's smartphone operating systems frequently fail to provide users with adequate control over and visibility into how third-party applications use their private data. We address these shortcomings with TaintDroid, an efficient, system-wide dynamic taint tracking and analysis system capable of simultaneously tracking multiple sources of sensitive data. TaintDroid provides realtime analysis by leveraging Android's virtualized execution environment. TaintDroid incurs only 14% performance overhead on a CPU-bound micro-benchmark and imposes negligible overhead on interactive third-party applications. Using TaintDroid to monitor the behavior of 30 popular third-party Android applications, we found 68 instances of potential misuse of users' private information across 20 applications. Monitoring sensitive data with TaintDroid provides informed use of third-party applications for phone users and valuable input for smartphone security service firms seeking to identify misbehaving applications.

Symbolic Boolean manipulation with ordered binary-decision diagrams

Abstract: Ordered Binary-Decision Diagrams (OBDDs) represent Boolean functions as directed acyclic graphs. They form a canonical representation, making testing of functional properties such as satisfiability and equivalence straightforward. A number of operations on Boolean functions can be implemented as graph algorithms on OBDD data structures. Using OBDDs, a wide variety of problems can be solved through symbolic analysis. First, the possible variations in system parameters and operating conditions are encoded with Boolean variables. Then the system is evaluated for all variations by a sequence of OBDD operations. Researchers have thus solved a number of problems in digital-system design, finite-state system analysis, artificial intelligence, and mathematical logic. This paper describes the OBDD data structure and surveys a number of applications that have been solved by OBDD-based symbolic analysis.

Physical unclonable functions for device authentication and secret key generation

Abstract: Physical Unclonable Functions (PUFs) are innovative circuit primitives that extract secrets from physical characteristics of integrated circuits (ICs). We present PUF designs that exploit inherent delay characteristics of wires and transistors that differ from chip to chip, and describe how PUFs can enable low-cost authentication of individual ICs and generate volatile secret keys for cryptographic operations.