Charge-Dependent Correlations in Relativistic Heavy Ion Collisions and the Chiral Magnetic Effect

We provide a phenomenological analysis of present experimental searches for local parity violation manifested through the Chiral Magnetic Effect. We introduce and discuss the relevant correlation functions used for the measurements. Our analysis of the available data from both RHIC and LHC shows that the present experimental evidence for the Chiral Magnetic Effect is rather ambiguous. We further discuss in some detail various background contributions due to conventional physics, which need to be understood quantitatively in order to draw a definitive conclusion about the existence of local parity violation in heavy ion collisions.Comment: 37 pages, to appear in Lect. Notes Phys. "Strongly interacting matter in magnetic fields" (Springer), edited by D. Kharzeev, K. Landsteiner, A. Schmitt, H.-U. Ye

Selective Document Retrieval from Encrypted Database

We propose the concept of selective document retrieval (SDR) from an encrypted database which allows a client to store encrypted data on a third-party server and perform efficient search remotely. We propose a new SDR scheme based on the recent advances in fully homomorphic encryption schemes. The proposed scheme is secure in our security model and can be adapted to support many useful search features, including aggregating search results, supporting conjunctive keyword search queries, advanced keyword search, search with keyword occurrence frequency, and search based on inner product. To evaluate the performance, we implement the search algorithm of our scheme in C. The experiment results show that a search query takes only 47 seconds in an encrypted database with 1000 documents on a Linux server, and it demonstrates that our scheme is much more efficient, i.e., around 1250 times faster, than a solution based on the SSW scheme with similar security guarantees

On the (im)possibility of projecting property in prime-order setting

Abstract. Projecting bilinear pairings have frequently been used for designing cryptosystems since they were first derived from composite order bilinear groups. There have been only a few studies on the (im)possibility of projecting bilinear pairings. Groth and Sahai (EUROCRYPT 2008) showed that projecting bilinear pairings can be achieved in a prime-order group setting. They constructed both projecting asymmetric bilinear pairings and projecting symmetric bilinear pairings, where a bilinear pairing e is symmetric if it satisfies e(g, h) = e(h, g) for any group elements g and h; otherwise, it is asymmetric. Subsequently, Freeman (EUROCRYPT 2010) generalized Groth-Sahai’s projecting asymmetric bilinear pairings. In this paper, we provide impossibility results on projecting bilinear pairings in a prime-order group setting. More precisely, we specify the lower bounds of 1. the image size of a projecting asymmetric bilinear pairing 2. the image size of a projecting symmetric bilinear pairing 3. the computational cost for a projecting asymmetric bilinear pairing 4. the computational cost for a projecting symmetric bilinear pairing in a prime-order group setting naturally induced from the k-linear assumption, where the computationa