Atomic Swap Research Articles

Atomic cross-chain swap based on private key exchange

Atomic Cross-Chain Swap (ACCS) is one important topic in cryptocurrency, where users can securely and trustlessly exchange assets between two different blockchains. However, most known ACCS schemes assume specific scripting functionalities of the underlying blockchains, such as Hash Time Locked Contracts (HTLC). In addition, these schemes are typically only applicable to certain digital signature schemes, like Schnorr or Elliptic Curve Digital Signature Algorithm (ECDSA) signatures. In this paper, we propose a generic ACCS scheme, independent from the underlying blockchains. To the best of our knowledge, this is the first solution of this kind. Our results are as follows. First, we define a formal system model of ACCS. Next, we present a generic ACCS scheme meets our model. This scheme admits atomicity in cross-chain swaps without the need for a Trusted Third Party (TTP) and protects users’ privacy. Finally, by using the Non-Interactive Zero-Knowledge (NIZK) proof protocol as a tool, we instantiate our generic scheme for Elliptic Curve Discrete Logarithm Problem-based (ECDLP-based) signatures. In addition, we implement our scheme, and the experimental results show that our protocol outperforms the existing ACCS schemes, such as the HTLC-based schemes.

Adaptor signature based on randomized EdDSA in blockchain

Adaptor signature, a new primitive that alleviates the scalability issue of blockchain to some extent, has been widely adopted in the off-chain payment channel and atomic swap. As an extension of standard digital signature, adaptor signature can bind the release of a complete digital signature with the exchange of a secret value. Existing constructions of adaptor signatures are mainly based on Schnorr or ECDSA signature algorithms, which suffer low signing efficiency and long signature length. In this paper, to address these issues, we propose a new construction of adaptor signature using randomized EdDSA, which has Schnorr-like structure with higher signing efficiency and shorter signature length. We prove the required security properties, including unforgeability, witness extractability and pre-signature adaptability, of the new adaptor signature scheme in the random oracle model. We conduct a comparative analysis with an ECDSA-based adaptor signature scheme to demonstrate the effectiveness and feasibility of our new proposal.

Effect of swap and antisite disorder on electronic, mechanical and thermodynamic properties of equiatomic all-d-metal Heusler alloy NiVTiZn

The influence of atomic disorder on electronic, mechanical and thermodynamic properties of equiatomic quaternary all-d metal Heusler alloy NiVTiZn is studied by employing the first-principles calculations. The ground state of NiVTiZn is confirmed to be α-type structure with ferromagnetic nature, the calculated spin down energy gap and equilibrium lattice constant is ∼0.7 eV and 6.048 Å, respectively. The half metallicity could be maintained when uniaxial strain ratio increases from −7.28 % to 9.59 % and when c/a ratio ranges from 0.92 to 1.06, showing a robust half metallicity against the strain effect and tetragonal distortion. Six types of atomic swap disorder and twelve types of atomic antisite disorder are proposed. The V(Ni) and V(Zn) antisite disorders as well as V-Ni and V-Zn swap disorders are the most favorable owing to their negative formation energies. The 100 % spin polarization is preserved in V(Ti), Ni-Zn and V-Ti disordered structures although the width of band gap suffers contraction. The spin polarization of Ni(V), Ni(Zn), V(Zn) and Zn(Ni) disordered structures is also larger than 80 %. In addition, the effect of various disorder on mechanical and thermodynamic properties is also studied in detail.

Threshold/Multi Adaptor Signature and Their Applications in Blockchains

Adaptor signature is a variant of digital signatures and useful for fair excheng in financial applications such as cryptocurrencies, to name a few, off-chain transaction protocols, atomic swaps and other privacy-enhancing mechanisms. However, similar to normal digital signatures, an adaptor signature also suffers from the loss of the secret key and single-point failure, which is insufficient in practice. In this paper, we address this constraint by introducing two new concepts as enhancements: multi-adaptor signatures and threshold adaptor signatures. First, we propose the formal security models for multi-adaptor signature and threshold adaptor signature. Then, we present specific schemes for these two primitives based on the commonly used blockchain signature scheme Schnorr and the post-quantum signature scheme Dilithium, respectively. Furthermore, we provide security proofs for these four schemes. Finally, we demonstrate interesting applications for blockchains, such as oracle-based conditional payment and n to n atomic swap.

Technical, forensic and organisational aspects of work with Monero cryptocurrency

The forensic, organisational and technical features of law enforcement agencies' work with the Monero cryptocurrency in the context of pre-trial investigation and operational search activities are analysed. The development of the Monero system is described. The reasons and trends of Monero use by offenders are identified, and the scheme of operation of this payment system, which ensures its increased confidentiality, is shown. Examples of criminal offences in which Monero is used are presented. The functionality of OpenAlias to facilitate the work with Monero addresses is disclosed. The possibility of identifying participants in Monero transactions is studied. It is stated that there are currently no effective ways of such identification without knowledge of the public address and the corresponding keys, especially if users use additional security mechanisms such as connection to the TOR network.
 The features of forensic investigation of computer equipment used to work with Monero are revealed. It is established that the most effective is the study of traces of work with Monero, which are removed from the relevant computer equipment of the person of interest. Useful information can be stored in RAM, on a disc, and partially in network traffic. The article identifies artefacts that should be taken into account during inspection and search. Atomic Swaps of XMR are modelled to determine the trace pattern and identify artefacts of increased attention during forensic procedures. The fact that an atomic swap was carried out to obfuscate traces may be evidenced by the presence of specific software files on the disc used for this purpose.
 The algorithm for XMR withdrawal using multisig addresses has been proposed, from which funds can be withdrawn only when digital signatures of several persons are superimposed. The work of this algorithm in the test network Stagenet is modelled. It has been concluded that law enforcement agencies should focus on classical investigative measures to identify Monero users of interest. At the same time, there are effective mechanisms for documenting traces of work with the Monero payment system and proven methods for extracting passphrases to crypto-wallets and other sensitive information on the movement of funds in the Monero system from computer equipment.

Theoretical study on the electronic properties and quantum capacitance ofZr2CO2MXenewith atomic swap

AbstractMXenes have the excellent electrochemical properties as electrode of supercapacitors. Using density functional theory, we investigated the electronic properties and quantum capacitance of Zr2CO2with atomic swap. The atomic swap results in the appearance of Frenkel‐type defect and Schottky defect. The negative binding energy confirms the stability of the studied systems. The atomic swap makes ZrC1, ZrC2, ZrO1, ZrO2, CO2 systems maintain the indirect semiconductor character, and CO2 system has the direct semiconductor character. The thermionic emission performance of Zr2CO2MXene is greatly improved by atomic swap. ZrO1 and ZrO2 systems in aqueous system are appropriate anode materials. The wide voltage has little effect on the electrode type for perfect Zr2CO2, ZrO1, ZrO2, CO1, and CO2 systems, but changes ZrC1 and ZrC2 systems from cathode material in aqueous system to anode material in ionic/organic system. The work function and effective mass are also explored.

Atomic cross-chain swaps with improved space, time and local time complexities

An effective atomic cross-chain swap protocol is introduced by Herlihy [Herlihy, 2018] as a distributed coordination protocol in order to exchange assets across multiple blockchains among multiple untrusted parties. The atomic cross-chain swap protocol guarantees; (1) if all parties conform to the protocol, then all assets are exchanged among the parties, (2) even if some parties or coalitions of parties deviate from the protocol, no party conforming to the protocol suffers a loss, and (3) no coalition has an incentive to deviate from the protocol. Herlihy [Herlihy, 2018] invented this protocol by using hashed timelock contracts.A cross-chain swap is modeled as a directed graph D=(V,A). Vertex set V denotes a set of parties and arc set A denotes a set of proposed asset transfers. Let Δ be time enough for a party to publish a contract on any of the blockchains, or to change the state of a contract and for the other party to detect the change. The space complexity of the protocol is O(|A|2). The local time complexity of the protocol is O(|V|⋅|L|), where L is a feedback vertex set computed by the protocol. We propose a new atomic cross-chain swap protocol which uses only signature information and improves the space complexity to O(|A|⋅|V|) and the local time complexity to O(|V|). Moreover, if all parties conform to our protocol, our proposed protocol improves the time complexity from O(|V|Δ) to O(Δ).

Zswap: zk-SNARK Based Non-Interactive Multi-Asset Swaps

Privacy-oriented cryptocurrencies, like Zcash or Monero, provide fair transaction anonymity and confidentiality, but lack important features compared to fully public systems, like Ethereum. Specifically, supporting assets of multiple types and providing a mechanism to atomically exchange them, which is critical for e.g. decentralized finance (DeFi), is challenging in the private setting. By combining insights and security properties from Zcash and SwapCT (PETS 21, an atomic swap system for Monero), we present a simple zk-SNARKs based transaction scheme, called Zswap, which is carefully malleable to allow the merging of transactions, while preserving anonymity. Our protocol enables multiple assets and atomic exchanges by making use of sparse homomorphic commitments with aggregated open randomness, together with Zcash friendly simulation-extractable non-interactive zero-knowledge (NIZK) proofs. This results in a provably secure privacypreserving transaction protocol, with efficient swaps, and overall performance close to that of existing deployed private cryptocurrencies. It is similar to Zcash Sapling and benefits from existing code-bases and implementation expertise.

First-principles study on the effect of atomic swap on the electronic properties and quantum capacitance of Sc2CF2 monolayer

Two-dimensional materials have attracted great attention due to their excellent properties. In this paper, we conducted a theoretical study on the atomic swap within Sc2CF2 MXene. The geometric structure, electronic properties and quantum capacitance of Sc2CF2-SC↔F, Sc2CF2-SC↔Sc, and Sc2CF2-SF↔Sc monolayers are investigated by first-principles calculation. Sc2CF2-SC↔Sc and Sc2CF2-SF↔Sc monolayers form Frenkel-type defect structure after optimization. Pristine Sc2CF2 is an indirect semiconductor, while the atomic swap has no effect on the semiconductor character of Sc2CF2-SC↔F, Sc2CF2-SC↔Sc, and Sc2CF2-SF↔Sc monolayers. Especially, the atomic swap between C and Sc atoms make Sc2CF2-SC↔Sc monolayer become a narrow direct semiconductor. The quantum capacitances in aqueous and ionic/organic systems are further investigated. In aqueous and ionic/organic electrolyte, Sc2CF2 and Sc2CF2-SF↔Sc are more suitable for cathode materials, while Sc2CF2-SC↔Sc monolayer is suitable for anode materials. Sc2CF2-SC↔F is transformed from a potential cathode material to a potential electrode material for symmetric supercapacitors with the extension of voltage. The effective mass and work function of the systems are further explored. The electronic properties and quantum capacitance of Sc2CT2 with mixed termination groups are also investigated.

Structural insight using anomalous XRD into Mn2CoAl Heusler alloy films grown by magnetron sputtering, IBAS, and MBE techniques

Inverse Heusler alloy Mn2CoAl thin films, known as a spin-gapless semiconductor (SGS), grown by three different methods—ultra-high vacuum magnetron sputtering, Ar-ion beam assisted sputtering, and molecular beam epitaxy—are investigated by comparing their electric transport properties, microstructures and atomic-level structures. Of the samples, the Mn2CoAl thin film grown by molecular beam epitaxy consists of Mn- and Co-rich phases, the structures of which are determined to be the L21B-type and disordered L21-type, respectively, according to anomalous X-ray diffraction analysis. None of them forms the XA-type structure expected for SGS Heusler alloy, although they all exhibit SGS characteristics. To validate the SGS characteristics, it is necessary to extract not only the magnetic and electric transport properties but also information about microstructures and atomic-scale structures of the films including defects such as atomic swap.

Investigation of structural, magnetic and electronic properties of CoMnSb superstructure: A DFT study

Using density functional theory (DFT) based electronic structure calculations, we have investigated the structural, magnetic and electronic properties of CoMnSb superstructure, to elucidate its physical properties and judge its suitability for device applications. We find that the fully optimized CoMnSb superstructure exhibits half metallicity in the bulk ordered structure with a half metallic gap of width ~0.22 eV and a total spin magnetic moment of 3.75 μB/f.u. (120 μB/unit cell). Furthermore, we have studied the role of intrinsic defects (anti-sites and atomic swaps) and strains (uniform and bi-axial) on the half metallic property of the superstructure. We find that the crystal structure of CoMnSb superstructure is stable against intrinsic defects and half metallicity is preserved for a few type of Co(Mn) atomic swap and anti-site defects. It is also observed that, half metallicity is retained for compressive uniform strain up to -3.0% and bi-axial strain up to -3.2%. As the width of the half metallic gap increases for isotropic strain and decreases for bi-axial strain, the former is a better choice for applications. We find that in a fully strained epitaxial thin film of CoMnSb superstructure deposited on GaAs(111) surface, half metallicity is expected to be retained, with the Ef lying within the gap. This condition is technologically more suitable compared to the unstrained condition, where the Ef lies at the top of the valence band.

Post-Quantum Two-Party Adaptor Signature Based on Coding Theory

An adaptor signature can be viewed as a signature concealed with a secret value and, by design, any two of the trio yield the other. In a multiparty setting, an initial adaptor signature allows each party to create additional adaptor signatures without the original secret. Adaptor signatures help address scalability and interoperability issues in blockchain. They can also bring some important advantages to cryptocurrencies, such as low on-chain cost, improved transaction fungibility, and fewer limitations of a blockchain’s scripting language. In this paper, we propose a new two-party adaptor signature scheme that relies on quantum-safe hard problems in coding theory. The proposed scheme uses a hash-and-sign code-based signature scheme introduced by Debris-Alazard et al. and a code-based hard relation defined from the well-known syndrome decoding problem. To achieve all the basic properties of adaptor signatures formalized by Aumayr et al., we introduce further modifications to the aforementioned signature scheme. We also give a security analysis of our scheme and its application to the atomic swap. After providing a set of parameters for our scheme, we show that it has the smallest pre-signature size compared to existing post-quantum adaptor signatures.

Blockchain Interoperability: Towards a Sustainable Payment System

The highly fragmented blockchain and cryptocurrency ecosystem necessitates interoperability mechanisms as a requirement for blockchain-technology acceptance. The immediate implication of interchain interoperability is automatic swapping between cryptocurrencies. We performed a systematic review of the existing literature on Blockchain interoperability and atomic cross-chain transactions. We investigated different blockchain interoperability approaches, including industrial solutions, categorized them and identified the key mechanisms used, and list several example projects for each category. We focused on the atomic transactions between blockchain, a process also known as atomic swap. Furthermore, we studied recent implementations along with architectural approaches for atomic swap and deduced research issues and challenges in cross-chain interoperability and atomic swap. Atomic swap can instantly transfer tokens and significantly reduce the associated costs without using any centralized authority, and thus facilitates the development of a sustainable payment system for wider financial inclusion.

An Ultra-Scalable Blockchain Platform for Universal Asset Tokenization: Design and Implementation

Since its introduction with Bitcoin in 2009, blockchain technology has received tremendous attention by academia, industry, politics and media alike, in particular, through extended blockchain-based visions such as smart contracts, decentralized finance, and, most recently, Web3. The critical prerequisite for any such blockchain-based vision to be turned into reality is uncapped scalability. Furthermore, and equally important, blockchain technology needs to transcend the stage of specialized tokens into an adaptive, heterogeneous tokenization platform. In this paper, we explain the Alphabill family of technologies that addresses both unlimited scalability and unrestricted adaptivity.We deliver a sharded blockchain technology with unlimited scalability and performance, called KSI Cash, which is based on a new form of electronic money scheme, the bill scheme. We present performance tests of KSI Cash that we have conducted with the European Central Bank and a group of eight national central banks from the Eurosystem in order to assess the technological feasibility of a digital euro.We show the system operating with 100 million wallets and 15 thousand transactions per second (under simulation of realistic usage); having an estimated carbon footprint of 0.0001g CO2 per transaction (Bitcoin = 100 kg and more). Furthermore, we show the system operating with up to 2 million payment orders per second, an equivalent of more than 300,000 transactions per second (in a laboratory setting with the central components of KSI Cash), scaling linearly in terms of the number of deployed shards. We explain, in detail, the key concepts that unlock this performance (i.e., the concepts of the bill money scheme). The results provide evidence that the scalability of our technology is unlimited in both permissioned and permissionless scenarios, resulting into the Alphabill Money technology. Next, we contribute the architecture of a universal tokenization platform that allows for universal asset tokenization, transfer and exchange as a global medium of exchange, called Alphabill platform. We reveal the crucial conceptual and technical contributions of the platform’s architecture and their interplay, including the data structures of KSI Cash and Alphabill Money, the dust collection solution of Alphabill Money, and the atomic swap solution of the Alphabill platform.

Lattice transformation in grain boundary migration via shear coupling and transition to sliding in face-centered-cubic copper

Migration of symmetric tilt grain boundaries (GBs) via shear coupling has been studied extensively in experiments and simulations. It was reported that shear coupling transitioned to GB sliding at high temperatures, but how such transition occurs at low temperatures has not been investigated. Lattice transformation on the atomic scale during shear coupling has not been fully understood. In this work, mode of motion of symmetric tilt GBs with [001] tilting axis in face centered cubic copper under a shear strain parallel to the boundary plane at 100 K was carefully characterized by tracking the positions of the corresponding planes in atomistic simulations and new features of GB motion were observed. The results show that the angles between the two low-index planes, (110) and (100), and the boundary plane can be used to define a nominal magnitude of shear s. Approximately, if one of these two planes has a value of s < 0.5, shear coupling occurs with this plane being the active invariant plane; if 0.5 < s < 0.6, GB moves by shear coupling + sliding, i.e. a hybrid mode by which shear coupling transitions to sliding; if both planes have a value of s> 0.6, only GB sliding occurs. Careful structural analyses show that, for all the GBs that undergo shear coupling, some GB atomic planes remain invariant, very similar to the first invariant plane in deformation twinning, whereas the other GB atomic planes swap their positions in the GB normal direction through highly coordinated and complex atomic shuffles. This behavior allows identification of transformation units that are reoriented toward the neighboring grain. Rate-limiting factors are identified for lattice transformation and can be used to infer a kinetics model for shear coupling.

Application of asset tokenization, smart contracts and decentralized finance in agriculture

"This is a study for applying Decentralized Finance (DeFi) operations in a real life Agricultural finance application focusing on how assets tokenization in general and crop insurance in particular may take advantage of fundraising, global capital markets, atomic swap operations over blockchain and finally peer-to-peer trading without intermediaries under standardized regulations and revolutionary custodial services. Descriptive statistical data presentations such as graphs and tables are used to do the analysis and evaluate the development of the sector. The paper is exploring the boundaries and the depth of Decentralized Finance while focusing on Asset Tokenization Application that are being deployed mainly in different agri-businesses starting with crop insurance and ending up with tokenizing the products over blockchain. In conclusion, asset tokenization as a representational digital asset for a traditional financial instrument is becoming an increasingly important part of modern finance and “blockchainization” of the real world. This paper addresses how agriculture sector as production sector can use asset tokenization in securing the crops by smart contracts and issuing digital tokens to fundraising for micro-insurance. Also, using blockchain to tokenize the crops for future contracts while in the same time boosting the efficiency of the agribusiness finance, crop insurance, trading in primary and secondary markets as well as exploring new markets without intermediaries, are aspects that are found in the present research."

On fair designs of cross‐chain exchange for cryptocurrencies via Monte Carlo simulation

AbstractCryptocurrency is one of the earliest and the most successful applications of blockchain, and it utilizes the distributed ledger, which is a commonly used technique in blockchain, to make a decentralized transaction within the blockchain of a cryptocurrency. However, how to make a decentralized transaction of cryptocurrencies between parties on different blockchains, that is, the cross‐chain exchange, is not well‐studied. In this paper, we develop a new method to make cross‐chain exchanges based on the classical atomic swap. We first study the optionality embedded into the atomic swap and propose to add a premium into the atomic swap, and then design a new procedure with the premium to guarantee the fairness of the cross‐chain exchange. We also provide an algorithm based on the least‐squares Monte Carlo method to estimate the premium and analyze the convergence of the algorithm. Moreover, we study the cross‐chain exchange with margin trading. We propose an adapted exchange procedure to make a fair cross‐chain exchange and an algorithm to estimate the fair premium under the margin trading. Numerical experiments are provided to show the effectiveness of the algorithms.

AucSwap: A Vickrey auction modeled decentralized cross-blockchain asset transfer protocol

With the rapid development of blockchain technology, the cross-blockchain asset transfer has been in great demand. However, most existing cross-blockchain solutions encounter low efficiency problems due to the centralized features, unfriendly development environment, and difficulty in cooperation. This paper proposes an interaction protocol for secure and efficient cross-blockchain transfer process, wherein the cross-blockchain asset transfer is modeled as an auction process. We design our protocol by leveraging the atomic swap technology and Vickrey auction scheme to achieve efficient cross-blockchain asset transfer, without sacrificing the decentralized control. To achieve the transfer efficiency, we optimize the Vickrey auction scheme to share data within the auction and delivery process synchronously. This results in a efficient user information exchange. The experimental results show that not only can our protocol achieve compatibility, but it also incurs little communication overhead in high throughput. A cross-blockchain transfer process can be accomplished in average 4 rounds of interaction. The difference between the transaction completion time and the bid waiting time is less than 1 second. Besides, our protocol guarantees the exchange rate at a reasonable range. The ratio of the cross-blockchain exchange rate to the real exchange rate converges to 0.9 for approximately 200 participants. The transaction fee decreases sharply with the increase of the number of auction participants.

Distributed Atomic Swap on Cryptocurrencies

Anyone who wants to trade something in his possession with something else desires three things: To trade at the most appropriate rate, to trade at the least cost, not to be exposed to theft and fraud during the clearing. The cryptocurrency swap is also no different from swapping of any two entities. Crypto-currencies are getting more and more attractive day by day because their stock exchanges are open 24/7. Although all crypto-money markets in the world have similar expectations, existing market models have difficulties and risks while operating on them. The problem of this research is centralized exchange markets and risks while operating on them. The study aims to develop a distributed exchange model on blockchain using smart contracts for atomic swap method, and payment channels technology for liquidity. With this model, users will pay less without taking risks of centralized exchange markets, like hacking, theft and fraud. In central exchanges, users first send their cryptocurrencies to the stock exchange's account to trade. This results in collection of all cryptocurrencies of users in a single pool. With this model, users will be allowed to wait in their wallets until the cryptocurrency is exchanged, and the risk of central hacking will be eliminated. Original contribution of this study to the literature is to combine Atomic Swap and Payment Channels technologies to create a liquid decentralized stock market model as much as central exchanges. Keywords : Atomic Swap Between Cryptocurrencies, Block-Chain; Cryptocurrency; Distributed Cryptocurrency Market; Cryptocurrency Payment Gateway DOI : 10.7176/CEIS/11-4-05 Publication date :August 31st 2020

Atomic commitment across blockchains

The recent adoption of blockchain technologies and open permissionless networks suggest the importance of peer-to-peer atomic cross-chain transaction protocols. Users should be able to atomically exchange tokens and assets without depending on centralized intermediaries such as exchanges. Recent peer-to-peer atomic cross-chain swap protocols use hashlocks and timelocks to ensure that participants comply to the protocol. However, an expired timelock could lead to a violation of the all-or-nothing atomicity property. An honest participant who fails to execute a smart contract on time due to a crash failure, denial of service attacks or even network delays might end up losing assets. Although a crashed participant is the only participant who ends up worse off, current proposals are unsuitable for atomic cross-chain transactions in asynchronous environments where crash failures and network delays are the norm. In this paper, we present AC 3 WN, the first decentralized all-or-nothing atomic cross-chain commitment protocol. The redeem and refund events of the smart contracts that exchange assets are modeled as conflicting events. An open permissionless network of witnesses is used to guarantee that conflicting events could never simultaneously occur and either all smart contracts in an atomic cross-chain transaction are redeemed or all of them are refunded.