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We propose a new, communication-efficient way for users to fetch multiple blocks simultaneously in Goldberg's robust information-theoretic private information retrieval (IT-PIR) scheme. Our new multi-block IT-PIR trades off some Byzantine robustness to improve throughput without affecting user privacy. By taking advantage of the recent Cohn-Heninger(More)
In this work, we propose a new platform to enable service providers, such as web site operators, on the Internet to block past abusive users of anonymizing networks (for example, Tor) from further misbehaviour, without compromising their privacy, and while preserving the privacy of all of the non-abusive users. Our system provides a privacy-preserving(More)
We extend Goldberg's multi-server information-theoretic private information retrieval (PIR) with a suite of protocols for privacy-preserving e-commerce. Our first protocol adds support for single-payee tiered pricing, wherein users purchase database records without revealing the indices or prices of those records. Tiered pricing lets the seller set prices(More)
Anonymous communications networks, such as Tor, help to solve the real and important problem of enabling users to communicate privately over the Internet. However, in doing so, anonymous communications networks introduce an entirely new problem for the service providers -- such as websites, IRC networks or mail servers -- with which these users interact, in(More)
Recruitment of endosomal sorting complexes required for transport (ESCRTs) to the cytosolic face of endosomes regulates selective inclusion of transmembrane proteins into the lumenal vesicles of multivesicular bodies (MVBs). ESCRT-0, -I, and -II bind directly to ubiquitinated transmembrane cargoes of the MVB pathway, whereas polymerization of ESCRT-III at(More)
We present several extensions to the Nymble framework for anonymous blacklisting systems. First, we show how to distribute the Verinym Issuer as a threshold entity. This provides liveness against a threshold Byzantine adversary and protects against denial-of-service attacks. Second, we describe how to revoke a user for a period spanning multiple link(More)
This paper chronicles our experiences using CUDA to implement a parallelized variant of Pollard's rho algorithm to solve discrete logarithms in groups with cryptographically large moduli but smooth order using commodity GPUs. We first discuss some key design constraints imposed by modern GPU architectures and the CUDA framework, and then explain how we were(More)
This paper examines " batch zero-knowledge " protocols for communication-and computation-efficient proofs of propositions composed of many simple predicates. We focus specifically on batch protocols that use Cramer, Damgård, and Schoenmakers' proofs of partial knowledge framework (Crypto 1994) to prove propositions that may be true even when some of their(More)
We present BLACRONYM, a suite of new communication- and computation-efficient protocols for anonymous blacklisting without trusted third parties. Our protocols improve on Tsang et al.'s Blacklistable Anonymous Credentials (BLAC) system and its variants by incorporating novel batch zero-knowledge proof and verification techniques. BLACRONYM provides(More)