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Pappu Srinivasa Ravikanth

Bio: Pappu Srinivasa Ravikanth is an academic researcher from Massachusetts Institute of Technology. The author has contributed to research in topics: One-way function & Physical system. The author has an hindex of 1, co-authored 1 publications receiving 1489 citations.

Papers
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Journal ArticleDOI
01 Jan 2001-Science
TL;DR: The concept of fabrication complexity is introduced as a way of quantifying the difficulty of materially cloning physical systems with arbitrary internal states as primitives for physical analogs of cryptosystems.
Abstract: Modern cryptography relies on algorithmic one-way functions—numerical functions which are easy to compute but very difficult to invert. This dissertation introduces physical one-way functions and physical one-way hash functions as primitives for physical analogs of cryptosystems. Physical one-way functions are defined with respect to a physical probe and physical system in some unknown state. A function is called a physical one-way function if (a) there exists a deterministic physical interaction between the probe and the system which produces an output in constant time; (b) inverting the function using either computational or physical means is difficult; (c) simulating the physical interaction is computationally demanding and (d) the physical system is easy to make but difficult to clone. Physical one-way hash functions produce fixed-length output regardless of the size of the input. These hash functions can be obtained by sampling the output of physical one-way functions. For the system described below, it is shown that there is a strong correspondence between the properties of physical one-way hash functions and their algorithmic counterparts. In particular, it is demonstrated that they are collision-resistant and that they exhibit the avalanche effect, i.e., a small change in the physical system causes a large change in the hash value. An inexpensive prototype authentication system based on physical one-way hash functions is designed, implemented, and analyzed. The prototype uses a disordered three-dimensional microstructure as the underlying physical system and coherent radiation as the probe. It is shown that the output of the interaction between the physical system and the probe can be used to robustly derive a unique tamper-resistant identifier at a very low cost per bit. The explicit use of three-dimensional structures marks a departure from prior efforts. Two protocols, including a one-time pad protocol, that illustrate the utility of these hash functions are presented and potential attacks on the authentication system are considered. Finally, the concept of fabrication complexity is introduced as a way of quantifying the difficulty of materially cloning physical systems with arbitrary internal states. Fabrication complexity is discussed in the context of an idealized machine—a Universal Turing Machine augmented with a fabrication head—which transforms algorithmically minimal descriptions of physical systems into the systems themselves. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

1,665 citations

Journal ArticleDOI
TL;DR: In this article , an adaptive recursive digital filter is used in better way to the maximum results with grid-connected solar PV-electric vehicle battery system, the system with recursive filter control is controllable when the solar insolation is changing and load demand change.
Abstract: The main aim of the project is to develop a system to charge the electric vehicle battery continuously and to control the three phase grid system. The perturb and observe method is used to get the maximum power from the solar PV array. The electric vehicle battery is connected at bi directional converter at the DC link and the Dc link is also connected at to the voltage source converter, this electric vehicle battery gets charged at low load demand and discharged at high load demand. This converter usually maintains the maximum power at the DC link by this the electric vehicle battery can be charged by taking a low rated battery to store energy of extra power. An adaptive recursive digital filter is used in better way to the maximum results with grid-connected solar PV-Electric vehicle battery system. The system with recursive filter control is controllable when the solar insolation is changing and load demand change. VSC works efficiently without any disturbance under no solar power generation and transfers the reactive power to the grid. The project is done with the help of simulation in MATLAB and test results on a hardware prototype is done through both in steady state conditions and dynamic conditions.

Cited by
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Proceedings ArticleDOI
04 Jun 2007
TL;DR: This work presents PUF designs that exploit inherent delay characteristics of wires and transistors that differ from chip to chip, and describes how PUFs can enable low-cost authentication of individual ICs and generate volatile secret keys for cryptographic operations.
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.

2,014 citations

Journal ArticleDOI
TL;DR: This survey examines approaches proposed by scientists for privacy protection and integrity assurance in RFID systems, and treats the social and technical context of their work.
Abstract: This paper surveys recent technical research on the problems of privacy and security for radio frequency identification (RFID). RFID tags are small, wireless devices that help identify objects and people. Thanks to dropping cost, they are likely to proliferate into the billions in the next several years-and eventually into the trillions. RFID tags track objects in supply chains, and are working their way into the pockets, belongings, and even the bodies of consumers. This survey examines approaches proposed by scientists for privacy protection and integrity assurance in RFID systems, and treats the social and technical context of their work. While geared toward the nonspecialist, the survey may also serve as a reference for specialist readers.

1,994 citations

Proceedings Article
01 Jan 2007

1,944 citations

Proceedings ArticleDOI
18 Nov 2002
TL;DR: It is argued that a complex integrated circuit can be viewed as a silicon PUF and a technique to identify and authenticate individual integrated circuits (ICs) is described.
Abstract: We introduce the notion of a Physical Random Function (PUF). We argue that a complex integrated circuit can be viewed as a silicon PUF and describe a technique to identify and authenticate individual integrated circuits (ICs).We describe several possible circuit realizations of different PUFs. These circuits have been implemented in commodity Field Programmable Gate Arrays (FPGAs). We present experiments which indicate that reliable authentication of individual FPGAs can be performed even in the presence of significant environmental variations.We describe how secure smart cards can be built, and also briefly describe how PUFs can be applied to licensing and certification applications.

1,644 citations

Journal ArticleDOI
TL;DR: Focusing of coherent light through opaque scattering materials by control of the incident wavefront with a brightness up to a factor of 1000 higher than the brightness of the normal diffuse transmission is reported.
Abstract: We report focusing of coherent light through opaque scattering materials by control of the incident wavefront. The multiply scattered light forms a focus with a brightness that is up to a factor of 1000 higher than the brightness of the normal diffuse transmission.

1,624 citations