Noninteractive Verifiable Outsourcing Algorithm for Bilinear Pairing with Improved Checkability

It is well known that the computation of bilinear pairing is the most expensive operation in pairing-based cryptography. In this paper, we propose a noninteractive verifiable outsourcing algorithm of bilinear pairing based on two servers in the one-malicious model. The outsourcer need not execute any expensive operation, such as scalar multiplication and modular exponentiation. Moreover, the outsourcer could detect any failure with a probability close to 1 if one of the servers misbehaves. Therefore, the proposed algorithm improves checkability and decreases communication cost compared with the previous ones. Finally, we utilize the proposed algorithm as a subroutine to achieve an anonymous identity-based encryption (AIBE) scheme with outsourced decryption and an identity-based signature (IBS) scheme with outsourced verification

Metamagnetic transitions and anomalous magnetoresistance in EuAg4_4As2_2 single crystal

In this paper, the magnetic and transport properties were systematically studied for EuAg$_4$As$_2$ single crystals, crystallizing in a centrosymmetric trigonal CaCu$_4$P$_2$ type structure. It was confirmed that two magnetic transitions occur at $\textit{T}$$_{N1}$ = 10 K and $\textit{T}$$_{N2}$ = 15 K, respectively. With the increasing field, the two transitions are noticeably driven to lower temperature. At low temperatures, applying a magnetic field in the $\textit{ab}$ plane induces two successive metamagnetic transitions. For both $\textit{H}$ $\parallel$ $\textit{ab}$ and $\textit{H}$ $\parallel$ $\textit{c}$, EuAg$_4$As$_2$ shows a positive, unexpected large magnetoresistance (up to 202\%) at low fields below 10 K, and a large negative magnetoresistance (up to -78\%) at high fields/intermediate temperatures. Such anomalous field dependence of magnetoresistance may have potential application in the future magnetic sensors. Finally, the magnetic phase diagrams of EuAg$_{4}$As$_{2}$ were constructed for both $\textit{H}$ $\parallel$ $\textit{ab}$ and $\textit{H}$ $\parallel$ $\textit{c}$

Structure of TAR RNA Complexed with a Tat-TAR Interaction Nanomolar Inhibitor that Was Identified by Computational Screening

AbstractHIV-1 TAR RNA functions critically in viral replication by binding the transactivating regulatory protein Tat. We recently identified several compounds that experimentally inhibit the Tat-TAR interaction completely at a 100 nM concentration. We used computational screening of the 181,000-compound Available Chemicals Directory against the three-dimensional structure of TAR [1]. Here we report the NMR-derived structure of TAR complexed with acetylpromazine. This structure represents a new class of compounds with good bioavailability and low toxicity that bind with high affinity to TAR. NMR data unambiguously show that acetylpromazine binds only to the unique 5′ bulge site to which the Tat protein binds. Specificity and affinity of binding are conferred primarily by a network of base stacking and hydrophobic interactions. Acetylpromazine alters the structure of free TAR less than Tat peptides and neomycin do