Ideal Tightly Couple (t,m,n) Secret Sharing

As a fundamental cryptographic tool, (t,n)-threshold secret sharing ((t,n)-SS) divides a secret among n shareholders and requires at least t, (t<=n), of them to reconstruct the secret. Ideal (t,n)-SSs are most desirable in security and efficiency among basic (t,n)-SSs. However, an adversary, even without any valid share, may mount Illegal Participant (IP) attack or t/2-Private Channel Cracking (t/2-PCC) attack to obtain the secret in most (t,n)-SSs.To secure ideal (t,n)-SSs against the 2 attacks, 1) the paper introduces the notion of Ideal Tightly cOupled (t,m,n) Secret Sharing (or (t,m,n)-ITOSS ) to thwart IP attack without Verifiable SS; (t,m,n)-ITOSS binds all m, (m>=t), participants into a tightly coupled group and requires all participants to be legal shareholders before recovering the secret. 2) As an example, the paper presents a polynomial-based (t,m,n)-ITOSS scheme, in which the proposed k-round Random Number Selection (RNS) guarantees that adversaries have to crack at least symmetrical private channels among participants before obtaining the secret. Therefore, k-round RNS enhances the robustness of (t,m,n)-ITOSS against t/2-PCC attack to the utmost. 3) The paper finally presents a generalized method of converting an ideal (t,n)-SS into a (t,m,n)-ITOSS, which helps an ideal (t,n)-SS substantially improve the robustness against the above 2 attacks

Constructing Ideal Secret Sharing Schemes based on Chinese Remainder Theorem

Since $(t,n)$-threshold secret sharing (SS) was initially proposed by Shamir and Blakley separately in 1979, it has been widely used in many aspects. Later on, Asmuth and Bloom presented a $(t,n)$-threshold SS scheme based on the Chinese Remainder Theorem(CRT) for integers in 1983. However, compared with the most popular Shamir\u27s $(t,n)$-threshold SS scheme, existing CRT based schemes have a lower information rate, moreover, they are harder to construct. To overcome these shortcomings of the CRT based scheme, 1) we first propose a generalized $(t,n)$-threshold SS scheme based on the CRT for the polynomial ring over a finite field. We show that our scheme is ideal, i.e., it is perfect in security and has the information rate 1. By comparison, we show that our scheme has a better information rate and is easier to construct compared with existing threshold SS schemes based on the CRT for integers. 2) We show that Shamir\u27s scheme, which is based on the Lagrange interpolation polynomial, is a special case of our scheme. Therefore, we establish the connection among threshold schemes based on the Lagrange interpolation, schemes based on the CRT for integers and our scheme. 3) As a natural extension of our threshold scheme, we present a weighted threshold SS scheme based on the CRT for polynomial rings, which inherits the above advantages of our threshold scheme over existing weighted schemes based on the CRT for integers

Structures and stability of adsorbed methanol on TiO2 (110) surface studied by ab initio thermodynamics and kinetic Monte Carlo simulation

The structures and stability of adsorbed methanol on TiO2(110) surface have been extensively studied because of its application for direct hydrogen production and promoting hydrogen production in photocatalysis. In this work, combined with ab initio thermodynamics and kinetic Monte Carlo (KMC), a detailed microscopic picture of methanol adsorption structure on TiO2(110) surface at different conditions is mapped out for the first time. The thermodynamics analysis based on the density functional theory calculations shows that the methanol adsorption at coverage of 2/3 ML is prevailed at a very wide range of temperatures and pressures. The simulated temperature-programmed desorption (TPD) based on KMC indicates that the full monolayer adsorption methanol desorbs at about 150 K and the methanol dimer at a coverage of 2/3 ML is stable up to 250 K. At higher temperature, the methanol dimer becomes unstable and decomposes to the monomer, which desorbs from the surface at 350 K. The present simulated results agree well with the experimental TPD results

Grouped Secret Sharing Schemes Based on Lagrange Interpolation Polynomials and Chinese Remainder Theorem

In a t,n threshold secret sharing (SS) scheme, whether or not a shareholder set is an authorized set totally depends on the number of shareholders in the set. When the access structure is not threshold, (t,n) threshold SS is not suitable. This paper proposes a new kind of SS named grouped secret sharing (GSS), which is specific multipartite SS. Moreover, in order to implement GSS, we utilize both Lagrange interpolation polynomials and Chinese remainder theorem to design two GSS schemes, respectively. Detailed analysis shows that both GSS schemes are correct and perfect, which means any authorized set can recover the secret while an unauthorized set cannot get any information about the secret

A Review of Research Status and Prospect of Vacuum Insulated Tubing Insulation System

Vacuum heat insulating tubing is an important wellbore heat insulating facility for heavy oil thermal recovery at present. Its heat insulating performance directly affects the thermal recovery efficiency. The research on the heat insulating system of vacuum heat insulating tubing is of great significance to improve and improve the heat insulating performance and enhance the thermal recovery of heavy oil. This paper summarizes and analyses the current research status of vacuum insulated tubing insulation system. It elaborates the insulation structure, insulation materials, annular air charging and vacuum pumping, insulation coating and so on. It provides reference and reference for the future research of vacuum insulated tubing

Role of ReOx Species in Ni-Re/Al2O3 Catalyst for Amination of Monoethanolamine

The role of ReOx species in Ni-Re/Al2O3 catalyst for amination of monoethanolamine (MEA) was investigated using a combination of experimental (Raman spectroscopy, in situ X-ray photoelectron spectroscopy, transmission electron microscopy, X-ray diffraction, scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy line scan, and extended X-ray absorption fine structure) and theoretical (density functional theory (DFT)) methods. Characterization and simulation results indicate that rhenium oxide specie prefers to atomically disperse on the surface of NiO in calcined Ni-Re/Al2O3 catalyst. After reduction, the surface of metallic Ni is decorated by ReOx with multiple valence states; meanwhile, a small amount of Ni-Re alloy was detected by extended X-ray absorption fine structure (EXAFS). DFT results indicate that different-valent ReOx species in Ni-Re/Al2O3 catalyst have different functions during reaction. The high-valent ReOx (x &gt;= 3) distributed on the Ni particle surface play an important role in decreasing the surface energy of Ni particle, thus stabilizing Ni particles against sintering and increasing the lifetime of Ni-Re/Al2O3 catalyst during amination reaction. The synergistic effect between Ni and low-valent ReOx (x &lt; 3) sites facilitates the abstraction of hydrogen in MEA and improves the activity of Ni-Re/Al2O3 catalyst for MEA amination

Commentary

Contains decisions taken by the International Criminal Tribunal for Rwanda in the year 2005. It provides the reader with the full text of the most important decisions