Preserving Buyer-Privacy in Decentralized Supply Chain Marketplaces

Technology is being used increasingly for lowering the trust barrier in domains where collaboration and cooperation are necessary, but reliability and efficiency are critical due to high stakes. An example is an industrial marketplace where many suppliers must participate in production while ensuring reliable outcomes; hence, partnerships must be pursued with care. Online marketplaces like Xometry facilitate partnership formation by vetting suppliers and mediating the marketplace. However, such an approach requires that all trust be vested in the middleman. This centralizes control, making the system vulnerable to being biased towards specific providers. The use of blockchains is now being explored to bridge the trust gap needed to support decentralizing marketplaces, allowing suppliers and customers to interact more directly by using the information on the blockchain. A typical scenario is the need to preserve privacy in certain interactions initiated by the buyer (e.g., protecting a buyer’s intellectual property during outsourcing negotiations). In this work, we initiate the formal study of matching between suppliers and buyers when buyer-privacy is required for some marketplace interactions and make the following contributions. First, we devise a formal security definition for private interactive matching in the Universally Composable (UC) Model that captures the privacy and correctness properties expected in specific supply chain marketplace interactions. Second, we provide a lean protocol based on any programmable blockchain, anonymous group signatures, and public-key encryption. Finally, we implement the protocol by instantiating some of the blockchain logic by extending the BigChainDB blockchain platform

Structural, Optical and Electrical Properties of Neodymium doped CdSe Thin Film

CdSe is a II-VI group material which has various applications in different areas of physics, such as display devices, solar cells, photodetectors, electro photography and lasers. The pure and different volumes of neodymium (Nd) doped CdSe thin films are prepared onto glass slides by chemical bath deposition method. The structural property shows the cubic structure of pure and Nd doped prepared thin film materials and the average crystal sizes 22.61 and 15.82nm for pure and Nd doped CdSe materials respectively. The optical bandgap energy were obtained in the range 1.98 and 2.02eV for pure and different volumes of Nd doped CdSe films. The electrical property shows the semiconducting behavior of the films. The samples also give increased dark current in the presence of neodymium. The absorption spectra exhibit the absorption of solar spectra in the visible range

Study of Ho doped Ag2S thin films prepared by CBD method

Ho doped Ag2S thin films were grown on the glass substrate by chemical bath deposition (CBD) method at room temperature. The bath contained aqueous solution of silver nitrate, thiourea, EDTA, ammonia and holmium nitrate. Silver nitrate was used as a silver (Ag+) ion source; thiourea as sulfur (S−) ion source, EDTA was a complexing agent while ammonia was used to maintain pH, Ho(NO3)3 was taken as a source of Ho ions. The optical absorption edge of undoped (pure) and Ho doped silver sulfide films was determined between 324 nm and 298 nm showing blue shift as compared to bulk Ag2S. Band gaps calculated from Tauc plot also showed an increase in values for doped samples. The increase in band gap indicates reduced particle size in the prepared Ho doped films. The photoluminescence emission peaks were observed at around 578 nm to 601 nm wavelength and excitation peaks were found at 351 nm to 294 nm for undoped and doped films. The SEM micrograph consists of globular ball type and flower type structures observed in the prepared films of Ho doped Ag2S