A Semantic Framework for the Security Analysis of Ethereum smart contracts

Smart contracts are programs running on cryptocurrency (e.g., Ethereum) blockchains, whose popularity stem from the possibility to perform financial transactions, such as payments and auctions, in a distributed environment without need for any trusted third party. Given their financial nature, bugs or vulnerabilities in these programs may lead to catastrophic consequences, as witnessed by recent attacks. Unfortunately, programming smart contracts is a delicate task that requires strong expertise: Ethereum smart contracts are written in Solidity, a dedicated language resembling JavaScript, and shipped over the blockchain in the EVM bytecode format. In order to rigorously verify the security of smart contracts, it is of paramount importance to formalize their semantics as well as the security properties of interest, in particular at the level of the bytecode being executed. In this paper, we present the first complete small-step semantics of EVM bytecode, which we formalize in the F* proof assistant, obtaining executable code that we successfully validate against the official Ethereum test suite. Furthermore, we formally define for the first time a number of central security properties for smart contracts, such as call integrity, atomicity, and independence from miner controlled parameters. This formalization relies on a combination of hyper- and safety properties. Along this work, we identified various mistakes and imprecisions in existing semantics and verification tools for Ethereum smart contracts, thereby demonstrating once more the importance of rigorous semantic foundations for the design of security verification techniques.Comment: The EAPLS Best Paper Award at ETAP

Synthesis and absorption and luminescence spectra of poly(methyl methacrylate):Cd(Mn,Pb)S composites

The reaction of cadmium, manganese, and lead trifluoroacetates with thioacetamide in methyl methacrylate yielded colloidal solutions of metal sulfides with different Cd(II): Mn(II): Pb(II) molar ratios. The colloidal particles were separated from solutions and examined by electron microscopy. Glassy polymer composites poly(methyl methacrylate):Cd(Mn)S and poly(methyl methacrylate):Cd(Mn,Pb)S were prepared by thermal polymerization of methyl methacrylate in the bulk. The transmittance of the composites at wavelengths larger than 480 nm is 92% at the sample thickness of 0.40 cm. The luminescence of the composites in the visible range is associated with cadmium sulfide. The corresponding absorption bands were recorded in the luminescence excitation spectra in the wavelength interval 300–450 nm. The effect of the matrix, Mn(II) and Pb(II) ions, and synthesis conditions on the absorption and luminescence properties of the composites was determined

Synthesis and spectral properties of colloidal solutions of metal sulfides

Cadmium, lead, and zinc sulfides as well as cadmium and lead (cadmium and zinc) complex sulfides have been synthesized in the colloidal state by reaction of metal trifluoroacetates with thioacetamide in ethyl acetate and methylmethacrylate. Synthesis products have been isolated from the reaction solutions and studied by X-ray diffraction, vibrational and electronic spectroscopy, and electronic microscopy. The effect of the composition on spectral properties of formulations has been discussed. The formation of colloidal particles and the stability of solutions are related to the complexation

ИМПОРТОЗАМЕЩЕНИЕ В РОССИИ: НАПРАВЛЕНИЯ И УСТОЙЧИВОСТЬ

The paper describes the regularities of the economic growth in the Russian Federation in 1998-2014 in terms of the “wages - productivity” gap. The scientific basis for the research into this structural imbalance includes findings of leading international financial institutions engaged in the study of the quality of the economic growth in mineral exporting countries. Based on this assessment two hypothetical trends of the Russian economic development after 2014 are formulated: beneficial and temporary import substitution. The main difference between the trends is the ability of tradable sectors to satisfy the temporarily reduced internal demand by replacing now much more expensive imports with high-quality substitutes. The index of non-mineral exports to far-abroad foreign countries was chosen as the quality criterion for domestically manufactured products. For quantitative assessments, the data of the Russian Statistics Service for 2013-2015 was used classified by the structure of the import substitution in the commodity markets, the dynamics of imports broken down by product groups and investments in these areas. The study showed the emerging prerequisites for the Russian economy movement towards favorable economic development. At the same time the paper considers the risks of failure to achieve a favorable outcome if the policy of the unbalanced growth of incomes through the resource rent rather than the productivity growth in the tradable non-mineral sectors continues.В статье рассмотрены закономерности экономического роста РФ в 1998-2014 гг. через призму разрыва «заработная плата - производительность». В качестве научной базы данного структурного дисбаланса использованы работы ведущих международных финансовых организаций, занимающихся изучением качества экономического роста в странах - экспортерах сырья. На основе этой оценки сформулированы две гипотетические траектории развития экономики России после 2014 г.: благоприятное и временное импортозамещение. Главным отличием траекторий является возможность торгуемых секторов обеспечить временно сниженный внутренний спрос качественной заменой подорожавшего импорта. Критерием качества производимой внутри страны продукции выбран показатель экспорта несырьевых товаров в страны дальнего зарубежья. Для количественных оценок были использованы данные Росстата за 2013-2015 гг. по структуре импортозамещения на товарных рынках, динамике импорта в разбивке по товарным группам и инвестиции в данные направления. Исследование показало наличие формирующихся предпосылок для выхода экономики РФ на благоприятную траекторию экономического развития. Вместе с этим в статье рассматриваются сохраняющиеся риски недостижения благоприятного исхода при продолжении политики несбалансированного роста доходов за счет сырьевой ренты, а не роста производительности в торгуемых несырьевых секторах

MV3: A new word based stream cipher using rapid mixing and revolving buffers

MV3 is a new word based stream cipher for encrypting long streams of data. A direct adaptation of a byte based cipher such as RC4 into a 32- or 64-bit word version will obviously need vast amounts of memory. This scaling issue necessitates a look for new components and principles, as well as mathematical analysis to justify their use. Our approach, like RC4's, is based on rapidly mixing random walks on directed graphs (that is, walks which reach a random state quickly, from any starting point). We begin with some well understood walks, and then introduce nonlinearity in their steps in order to improve security and show long term statistical correlations are negligible. To minimize the short term correlations, as well as to deter attacks using equations involving successive outputs, we provide a method for sequencing the outputs derived from the walk using three revolving buffers. The cipher is fast -- it runs at a speed of less than 5 cycles per byte on a Pentium IV processor. A word based cipher needs to output more bits per step, which exposes more correlations for attacks. Moreover we seek simplicity of construction and transparent analysis. To meet these requirements, we use a larger state and claim security corresponding to only a fraction of it. Our design is for an adequately secure word-based cipher; our very preliminary estimate puts the security close to exhaustive search for keys of size < 256 bits.Comment: 27 pages, shortened version will appear in "Topics in Cryptology - CT-RSA 2007

Making Micro- and Nano-beams by Channeling in Micro- and Nano-structures

A particle beam of very small cross-section is useful in many accelerator applications including biological and medical ones. We show the capability of the channeling technique using a micron-sized structure on a surface of a single crystal, or using a nanotube, to produce beam of a cross-section down to 1 square micrometer (or nanometer). The channeled beam can be deflected and thus well separated in angle and space from the primary and scattered particles. Monte Carlo simulation is done to evaluate the characteristics of a channeled microbeam. Emittances down to 0.1-0.001 nanometer radian, and flux up to 1 million particles per square micron per second, can be achieved for protons and ions.Comment: 8 pages, 4 figure

Superorbital variability of the X-ray flux in the Be-donor binaries SXP 138, GX-304, and γ Cas

© 2015, Pleiades Publishing, Ltd. RXTE observations of the X-ray binary systems SXP 138, GX-304, and γ Cas in 1997–2011 have shown for the first time that these objects (X-ray binaries with Be donors) display X-ray flux variations on timescales of ∼1000 days. This timescale is about 10 times longer than their orbital periods, and is comparable to the total time of the observations. The observed variations are apparently not strictly periodic and represent stochastic variability, as is characteristic of such systems in the optical. γ Cas is considered as an example. The series of optical observations of this system available in the AAVSO database covers 78 years, and is much longer than the timescale of the variability studied. Our analysis of this series has shown that γ Cas variability on a timescale of tens of years is predominantly stochastic with a power-law spectrum

Crystal Undulator As A Novel Compact Source Of Radiation

A crystalline undulator (CU) with periodically deformed crystallographic planes is capable of deflecting charged particles with the same strength as an equivalent magnetic field of 1000 T and could provide quite a short period L in the sub-millimeter range. We present an idea for creation of a CU and report its first realization. One face of a silicon crystal was given periodic micro-scratches (grooves), with a period of 1 mm, by means of a diamond blade. The X-ray tests of the crystal deformation have shown that a sinusoidal-like shape of crystalline planes goes through the bulk of the crystal. This opens up the possibility for experiments with high-energy particles channeled in CU, a novel compact source of radiation. The first experiment on photon emission in CU has been started at LNF with 800 MeV positrons aiming to produce 50 keV undulator photons.Comment: Presented at PAC 2003 (Portland, May 12-16

Cryptanalysis of the ISDB Scrambling Algorithm (MULTI2)

MULTI2 is the block cipher used in the ISDB standard for scrambling digital multimedia content. MULTI2 is used in Japan to se- cure multimedia broadcasting, including recent applications like HDTV and mobile TV. It is the only cipher specified in the 2007 Japanese ARIB standard for conditional access systems. This paper presents a theoretical break of MULTI2 (not relevant in practice), with shortcut key recovery attacks for any number of rounds. We also describe equivalent keys and linear attacks on reduced versions with up 20 rounds (out of 32), improv- ing on the previous 12-round attack by Matsui and Yamagishi. Practical attacks are presented on up to 16 rounds