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DEBORAH ESTRIN | Professor
Computer Science and Electrical Engineering
An Overview of CENS
Deborah Estrin is a Professor of Computer Science with a joint appointment in Electrical Engineering at UCLA. She holds the Jon Postel Chair in Computer Networks, and is the Founding Director of the NSF-funded Center for Embedded Networked Sensing (CENS). In 1985, Estrin received her Ph.D. in Computer Science from the Massachusetts Institute of Technology, and in 1980, she received her B.S from U.C. Berkeley. Before joining UCLA, she was a member of the University of Southern California, Computer Science Department.
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RAFAIL OSTROVSKY | Professor
Computer Science and Mathematics
CICS overview
In this talk, we survey the notion of Single-Database Private Information Retrieval (PIR). The first Single-Database PIR was constructed in 1997 by Kushilevitz and Ostrovsky. Since then, Single-Database PIR has emerged as an important cryptographic primitive. For example, Single-Database PIR turned out to be intimately connected to collision-resistant hash functions, oblivious transfer and public-key encryptions with additional properties. In this survey, we give an overview of many of the constructions for Single-Database PIR (including an abstract construction based upon homomorphic encryption) and describe some of the connections of PIR to other primitives.
Rafail Ostrovsky is a Professor of Computer Science and Mathematics at UCLA. Prof. Ostrovsky came to UCLA in 2003 from Telcordia Technologies (previously Bell Communications Research), where he was a senior research scientist in the Math Sciences Research Center. Prior to beginning his career at Telcordia, he was an NSF Mathematical Sciences Postdoctoral Fellow at UC Berkeley. Dr. Ostrovsky received his Ph.D. in computer science from MIT in the Theory of Computation Group of Laboratory for Computer Science in 1992.
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PETER REIHER | Professor
Computer Science
How to prevent IP spoofing
IP addresses can be easily spoofed, leading to various security problems. Building Internet defenses against spoofing is challenging, particularly because most approaches work poorly in partial deployment. Clouseau is a new approach that detects spoofing by observing traffic and making controlled tests of that traffic. This approach allows a single router to run Clouseau without any other machine in the Internet changing its behavior.
Peter Reiher is an adjunct associate professor in the Computer Science Department at UCLA and heads up the Laboratory for Advanced Systems Research (LASR). Peter received his B.S. in Electrical Engineering from the University of Notre Dame in 1979, and his M.S. and Ph.D. in Computer Science from UCLA in 1983 and 1987, respectively. Peter teaches graduate courses in the UCLA Computer Science Department on advanced operating systems, distributed operating systems, computer security, and experimental methodology for system software.
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ERIC OSTERWELL | Ph.D. Candidate
Computer Science
Leveraging the "Public-Space" to help Secure the Internet's Infrastructure
Designing and deploying systems in the Internet poses many unconventional challenges. The nature of the Internet is such that it is a uniquely large-scale environment and it is comprised of multiple independent parties who need not agree on issues such as trust and policies, and these parties may independently choose whether or not to adopt new protocols or enhancements. As a result, successful Internet systems must embrace heterogeneity, flexibility, complex failure modes, and the inevitability of partial deployments as first class principles. These necessities can often complicate the designs of cryptographic systems. We propose a general principle: public actions and behavior can be used to inform security systems and designs. Internet systems that allow local policy decisions and evaluations are very successful (BGP, DNS, etc.). By quantifying the public-space, we have designed a set of pilot applications that use cryptography to verify public data, but leave the security policy decisions to end-systems. We use the public-space to allow users to draw their own conclusions of trust and create their own policies using Internet-scale events and information.
Eric Osterwell is a Ph.D. student in the Computer Science Department at the University of California, Los Angeles, in the Internet Research Lab, under Professor Lixia Zhang. His previous experience includes eight years of industry software engineering at companies such as Micormuse (now owned by IBM) and Avaya. His current research interests center around Internet Security. He is the lead developer on the SecSpider project - the first DNSSEC deployment monitoring system - and BGP-Origins.
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MAJID SARRAFZADEH | Professor
Computer Science
Hackers Who Can Kill you
Majid Sarrafzadeh received his B.S., M.S. and Ph.D. in 1982, 1984, and 1987 respectively from the University of Illinois at Urbana-Champaign in Electrical and Computer Engineering. He joined Northwestern University as an Assistant Professor in 1987. In 2000, he joined the Computer Science Department at University of California at Los Angeles (UCLA). His recent research interests lie in the area of Embedded and Reconfigurable Computing, VLSI CAD, and design and analysis of algorithms.
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PAUL BUNN | Ph.D. Candidate
Mathematics
Optimal-Rate Routing in Adversarial Networks
This talk presents an optimal rate-routing protocol in the public-key setting for synchronous networks in the presence of a malicious poly-time adversary. Namely, even if the majority of the nodes are controlled by a malicious adversary and the topology of the network is changing at each round, then as long as there is some path of non- corrupted nodes connecting a sender and a receiver at each round (though this path may change every round), we construct a routing protocol with bounded memory per processor that achieves optimal packet transfer rate. The routing protocol assumes no knowledge of which nodes are corrupted nor which path is reliable at any round. Our result, which can be interpreted as the first interactive coding theorem for malicious networks, states that the protocol cannot be affected in a meaningful way by any polynomial-time malicious adversary whose goal is to disrupt the communication as much as possible. This includes, but not limited to: deletion, insertion, and replacement of any content, not responding or responding incorrectly to information requests, or any other arbitrary deviation from prescribed protocol rules.
Paul Bunn is a fifth-year graduate student in the math department at the University of California, Los Angeles. His research focuses on problems in number theory and theoretical computer science, including cyrptography and network and distributed algorithms. Bunn graduated with distincition from Duke University in 2001. with a double-major in Physics and Computer Science.
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NISANTH CHANDRAN | Ph.D. Candidate
Computer Science
Covert Multi-Party Computation
In STOC’05, Ahn, Hopper and Langford introduced the notion of covert computation. A covert computation protocol is one in which parties can run a protocol without knowing if other parties are also participating in the protocol or not. At the end of the protocol, if all parties participated in the protocol and if the function output is favorable to all parties, the output is revealed. Ahn et al. constructed a protocol for covert two-party computation in the random oracle model. In this talk, we offer a construction for covert multi-party computation. Our construction is in the standard model and does not require random oracles. In order to achieve this goal, we introduce a number of new techniques. Central to our work is the development of “zero-knowledge proofs to garbled circuits,” which we believe could be of independent interest. Along the way, we also develop a definition of covert computation as per the Ideal/Real model simulation paradigm.
Nishanth Chandran is a third-year doctoral student working with Professor Amit Sahai and Professor Rafail Ostrovsky. His research interests are cryptography, theory and security. Nishanth received a Bachelor’s degree in Computer Engineering from Anna University, India in 2005 and a Master’s degree in Computer Science from UCLA in 2007.
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AMIT SAHAI | Associate Professor
Computer Science
Efficient Non-Interactive Zero Knowledge
Non-interactive zero-knowledge (NIZK) systems are Fundamental cryptographic primitives used in many constructions, including CCA2-secure cryptosystems, digital signatures, and various cryptographic protocols. What makes them especially attractive is that they work equally well in a concurrent setting, which is notoriously hard for interactive zero-knowledge protocols. However, while for interactive zero-knowledge we know how to construct statistical zero-knowledge argument systems for all NP languages, for non-interactive zero-knowledge, this problem has remained open since the inception of NIZK in the late 1980’s. Here we resolve two problems regarding NIZK: --we construct the first perfect NIZK argument system for any NP language. --we construct the first UC-secure NIZK protocols for any NP language in the presence of a dynamic/adaptive adversary. While it was already known how to construct efficient prover computational NIZK proofs for any NP language, the known techniques yield large common reference strings and large NIZK proofs. As an additional implication of our techniques, we considerably reduce both the size of the common reference string and the size of the proofs.
Amit Sahai received his Ph.D. in Computer Science from MIT in 2000. From 2000 to 2004, he was a professor at Princeton University; in 2004 he joined UCLA as an Associate Professor of Computer Science, and as Associate Director of the Center for Information and Computation Security. His research interests are in security and cryptography, and theoretical computer science more broadly. He has published more than 60 original technical research papers at venues such as the ACM Symposium on Theory of Computing (STOC), CRYPTO, and the Journal of the ACM. He has given a number of invited talks at institutions such as MIT, Stanford, and Berkeley, including the 2004 Distinguished Cryptographer Lecture Series at NTT Labs, Japan. Professor Sahai is the recipient of numerous honors; he was named an Alfred P. Sloan Foundation Research Fellow in 2002, and received an Okawa Research Award in 2007.
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VIPUL GOYAL | Ph.D. Candidate
Computer Science
Reducing Trust in Identity Based Cryptosystems
One day, you suddenly find that a private key corresponding to your Identity is up for sale at e-Bay. Since you do not suspect a key compromise, perhaps it must be the PKG who is acting dishonestly and trying to make money by selling your key. How do you find out for sure and even prove it in a court of law? This paper introduces the concept of Accountable Authority Identity based Encryption (A- IBE). A-IBE is a new approach to mitigate the (inherent) key escrow problem in identity based encryption schemes. Our main goal is to restrict the ways in which the PKG can misbehave. In our system, if the PKG ever maliciously generates and distributes a decryption key for an Identity, it runs the risk of being caught and prosecuted. In contrast to other mitigation approaches, our approach does not require multiple key generation authorities.
Vipul Goyal is a graduate student at UCLA and is interested in cryptography and information security. His works include the topics of zero-knowledge proofs, secure multiparty computation, identity based encryption and program obfuscation. He has published papers at venues like CRYPTO, FOCS and ACM CCS.
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OMKANT PANDEY | Ph.D. Candidate
Computer Science
Attribute-Based Encryption for Fine-Grained Access Control of Encrypted Data
As more sensitive data is shared and stored by third-party sites on the Internet, there will be a need to encrypt data stored at these sites. One drawback of encrypting data, is that it can be selectively shared only at a coarse-grained level (i.e., giving another party your private key). We develop a new cryptosystem for Żne-grained sharing of encrypted data that we call Key-Policy Attribute-Based Encryption (KP-ABE). In our cryptosystem, ciphertexts are labeled with sets of attributes and private keys are associated with access structures that control which ciphertexts a user is able to decrypt. We demonstrate the applicability of our construction to sharing of audit-log information and broadcast encryption. Our construction supports delegation of private keys which subsumes Hierarchical Identity-Based Encryption (HIBE).
Omkant Pandey has been a Ph.D. student at UCLA since the fall of 2005. He works in Cryptography and Information Security. Omkant obtained his Bachelor's in Computer Science and Engineering in 2004, from Institute of Technology, Banaras Hindu University (IT-BHU), India.
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YUVAL ISHAI | Associate Professor
Computer Science at the Technion -- Israel Institute of Technology
Cryptography with Constant Computational Overhead
Current constructions of cryptographic primitives typically involve a large multiplicative computational overhead that grows with the desired level of security. We explore the possibility of implementing basic cryptographic primitives, such as encryption, authentication, signatures, and secure two-party computation, while incurring only a constant computational overhead compared to insecure
implementations of the same tasks. Here we make the usual security requirement that the advantage of any polynomial-time attacker must be negligible in the input length. We obtain affirmative answers to this question for most central cryptographic primitives under plausible, albeit sometimes nonstandard, intractability assumptions. We start by showing that pairwise-independent hash functions can be computed by linear-size circuits, disproving a conjecture of Mansour, Nisan, and Tiwari (STOC 1990). This construction does not rely on any unproven assumptions and is of independent interest. Our hash functions can be used to construct message authentication schemes with constant overhead from any one-way function. --Under an intractability assumption that generalizes a previous assumption of Alekhnovich (FOCS 2003), we get (public and private key) encryption schemes with constant overhead. Using an exponentially strong version of the previous assumption, we get signature schemes of similar complexity. --Assuming the existence of pseudorandom generators in NC0 with polynomial stretch together with the existence of an (arbitrary) oblivious transfer protocol, we get similar results for the seemingly very complex task of secure two-party computation. More concretely, we get general protocols for secure two-party computation in the semi-honest model in which the two parties can be implemented by circuits whose size is a constant multiple of the size s of the circuit to be evaluated. In the malicious model, we get protocols whose communication complexity is a constant multiple of s and whose computational complexity is slightly super-linear in s. For natural relaxations of security in the malicious model that are still meaningful in practice, we can also keep the computational complexity linear in s. These results extend to the case of a constant number of parties, where an arbitrary subset of the parties can be corrupted. Our protocols rely on non-black-box techniques, and suggest the intriguing possibility that the ultimate efficiency in this area of cryptography can be obtained via such techniques.
Yuval Ishai is an Associate Professor of Computer Science at the Technion -- Israel Institute of Technology, currently on a sabbatical leave at UCLA. He received his B.A. from the Technion in 1994 and his Ph.D. from the Technion in 1999. He joined the Technion in 2002 after a postdoc at DIMACS, AT&T Labs Research, and Princeton University. He is interested in cryptography and complexity theory.
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