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We define a novel notion of quasi-adaptive non-interactive zero-knowledge (NIZK) proofs for probability distributions on parameterized languages. It is quasi-adaptive in the sense that the common reference string (CRS) generator can generate the CRS depending on the language parameters. However, the simulation is required to be uniform, i.e., a single(More)
We state a switching lemma for tests on adversarial responses involving bilinear pairings in hard groups, where the tester can effectively switch the randomness used in the test from being given to the adversary at the outset to being chosen after the adversary commits its response. The switching lemma can be based on any k-linear hardness assumptions on(More)
The rice (Oryza sativa) genome contains a family of kaurene synthase-like genes (OsKSL) presumably involved in diterpenoid biosynthesis. While a number of OsKSL enzymes have been functionally characterized, several have not been previously investigated, and the gene family has not been broadly analyzed. Here we report cloning of several OsKSL genes and(More)
In a functional encryption scheme, secret keys are associated with functions and ciphertexts are associated with messages. Given a secret key for a function f and a ciphertext for a message x, a decryptor learns f(x) and nothing else about x. Inner product encryption is a special case of functional encryption where both secret keys and ciphertexts are(More)
This paper defines an ideal functionality for delegation of web access to a third-party where the authentication mechanism is password-based. We give a universally-composable (UC) realization of this ideal functionality assuming the availability of an SSL-like ideal functionality. We also show that this implementation can be further refined to give a(More)
In this paper, we describe a framework for a refinement scheme located in a centralized policy server that consists of three components: a knowledge database, a refinement rule set, and a policy repository. The refinement process includes two successive steps: policy transformation and policy composition. Our refinement scheme takes policies written in our(More)
We show that the recent structure-preserving signature (SPS) scheme of Kiltz, Pan and Wee [CRYPTO 2015], provably secure under the standard bilinear pairings group assumption SXDH, can be improved to have one less group element and one less pairing product equation in the signature verification step. Our improved SPS scheme only requires six group elements(More)
Traditional cryptographic hash functions allow one to easily check whether the original plaintexts are equal or not, given a pair of hash values. Probabilistic hash functions extend this concept where given a probabilistic hash of a value and the value itself, one can efficiently check whether the hash corresponds to the given value. However, given distinct(More)