Kesuksesan Bitcoin sebagai cryptocurrency, mendorong munculnya banyak cryptocurrency lain yang disebut sebagai altcoin. Sebagai pelopor cryptocurrency, volatilitas yang terjadi pada harga Bitcoin memiliki kemungkinan untuk memiliki efek menular (spillover) terhadap volatilitas harga altcoin. Begitu pula sebaliknya, harga altcoin yang terus menguat pun turut menciptakan kemungkinan bagi harga altcoin untuk memengaruhi harga Bitcoin. Sedangkan, sampel yang dipilih berdasarkan teknik purposive sampling adalah Bitcoin dan altcoin Ethereum, Ripple, Bitcoin Cash, dan EOS, karena memiliki kapitalisasi pasar paling tinggi berdasarkan website Cryptocurrency Market Capitalizations. Data yang digunakan adalah data time series berupa data harian harga penutupan Bitcoin dan altcoin Ethereum, Ripple, Bitcoin Cash, dan EOS yang diambil dari website Cryptocurrency Market Capitalizations. Kemudian, untuk dapat menjawab pertanyaan penelitian, data tersebut dianalisis menggunakan uji Augmented Dickey-Fuller, uji GARCH dan uji Granger Causality.
Hasil analisis menggunakan GARCH menunjukan bahwa terjadi volatility spillover antara Bitcoin dengan Ethereum serta Bitcoin dengan Bitcoin Cash. Lalu, uji Granger Causality menunjukan hasil bahwa volatility spillover yang terjadi antara Bitcoin dan Ethereum adalah hubungan kausalitas satu arah (tunggal) dari Bitcoin ke Ethereum. Sedangkan, pada Bitcoin dan Bitcoin Cash terjadi hubungan kausalitas dua arah (bilateral).
The blockchain-empowered mobile-edge computing (MEC) is a promising solution for enhancing the computation capabilities of mobile equipments (MEs) to process computation-intensive tasks such as the real-time data processing tasks and mining tasks. However, because of the “cold start” and “long return” problems, efficient computation offloading cannot be achieved in blockchain-empowered MEC because the MEs do not always have enough coins to afford the offloading service cost. In this article, we study the joint computation-offloading and coin-loaning problem for blockchain-empowered MEC to minimize the total cost of all MEs. We introduce the banks that can provide loan services to the MEs to address the above two issues. We formulate the problem as a noncooperative game to model the competitions between the myopic MEs. By using a potential game method, we prove the existence of a pure-strategy Nash equilibrium (NE) and design a distributed algorithm to achieve the NE point with low computational complexity. We also provide an upper bound on the price of anarchy of the game by theoretical proof. Besides, two smart contracts are designed to automatically perform the computing resource trading and coin loaning processes. Lastly, our simulation results show that our proposed algorithm can significantly reduce the total cost of all MEs, has better performance compared with other solutions, and scales well as the number of MEs increases. Moreover, the financial cost for executing the two smart contracts on the Ethereum network is low.
Ryan Shah, Michael McIntee, Shishir Nagaraja, Sahil Bhandary · 6 authors
Secure sensor calibration constitutes a foundational step that underpins operational safety in the Industrial Internet of Things. While much attention has been given to IoT security such as the use of TLS to secure sensed data, little thought has been given to securing the calibration infrastructure itself. Currently traceability is achieved via manual verification using paper-based datasheets which is both time consuming and insecure. For instance, when the calibration status of parent devices is revoked as mistakes or mischance is detected, calibrated devices are not updated until the next calibration cycle, leaving much of the calibration parameters invalid. Aside from error, any party within the calibration infrastructure can maliciously introduce errors since the current paper based system lacks authentication as well as non-repudiation. In this paper, we propose a novel resilient architecture for calibration infrastructure, where the calibration status of sensor elements can be verified on-the-fly to the root of trust preserving the properties of authentication and non-repudiation. We propose an implementation based on smart contracts on the Ethereum network. Our evaluation shows that Ethereum is likely to address the protection requirements of traceable measurements.
Open access
2 source records
cs.CR
Physical Unclonable Functions (PUFs) and Hardware Security
Due to the anonymity of cyrptocurrencies, a new method of money laundering that hides the source of illegal funds has emerged by utilizing cyrptocurrencies. In addition, there are cases such as exchange hacks or ICO frauds in which cryptocurrencies themselves are dirty money. These illegal actions are criticized as problems of cryptocurrencies, and these problems must be tackled for the sake of development and commercialization of cryptocurrencies. Although Ethereum is a public blockchain that is completely open anyone, it does not provide the necessary tools such as query language or client tools needed, therefore requiring further methods to process and utilize data efficiently. This paper aims to explore the money laundering that is happening in Ethereum. In addition, it suggests the ways to sort Ethereum accounts suspected of being used for money laundering and the strategy to implement them using Graph Database.
The process of determining something for the interests of the parties is called governance. Then we need to see if the current blockchain platforms, including Bitcoin and Ethereum, are well governed. Bitcoin is divided into several hard-forked platforms such as Bitcoin Cash, Bitcoin Gold and Bitcoin Diamond. Ethereum is represented by Ethereum and Ethereum Classic. If BIP(Bitcoin Improvement Proposals) or EIP(Ethereum Improvement Proposals) had a well-communicated and smooth negotiation process in adavance, it would not have reached the extreme of being hard-forked with multiple chains. In this paper, we analyze on-chain and off-chain governanace of blockchain and propose a new on-chain governance platform that can be mediated and upgraded in the blockchain.
This paper describes a new way to create a pre-authorized transaction on the blockchain so that the transaction is less likely to have errors. Currently, cryptocurrency transactions do not allow a sender to modify or cancel a transaction that has been sent to a wrong address or person. There is no way for the user to retrieve the funds, and the receiver may not return any coins or data. Thus, if a user sends a coin or data to a wrong or non-existent party the coin or data is permanently lost once the transaction is accepted in the blockchain. Current blockchain frameworks such as Bitcoin and Ethereum share this unidirectional technical standard. It is also possible to make it appear that a recipient is taking a bribe by sending them cryptocurrency without their permission. We define a new protocol of pre-authorization in which all parties agree and sign, and the blockchain ratifies the resulting agreement. While nothing will eliminate all risk of error and fraud, this proposal will prevent these kinds of losses.
In recent years, the Ethereum platform has rapidly emerged, but its privacy issue has become the largest obstacle to the implementation of Ethereum projects. Unlike UTXO-based Bitcoin, Ethereum, the account-based blockchain, requires realtime updates of the account balance. Therefore, its corresponding hidden operation has certain difficulties. We propose a privacy protection scheme called RZcash to solve this problem. It implements the hiding of account balances that are updated in real time, and uses rangeproofs to ensure that the amount of each transaction does not exceed the payer's existing balance. For hiding the payee, we improve the related technology of Monero by using the ciphertext equivalent commitment scheme. We also provide the conversion mechanism and trading method between hidden coins and open coins and describe how RZcash can be combined with an existing account-based blockchain system (such as Ethereum). Finally, we implement the core model of RZcash and evaluate its performance. The evaluation results show that the scheme not only guarantees the privacy and security of the blockchain, but also has good performance in practical applications.
As the monetary value of cryptocurrency increases, the security measures for cryptocurrency becomes more important. A limitation of the existing cryptocurrency exchanges is their vulnerability to threats of hacking due to their centralized manner of management. In order to overcome such limitation, blockchain technology is increasingly adopted. The blockchain technology enables decentralization and Peer-to-Peer(P2P) transactions, in which blocks of information are linked in chain topology, and each node participating in the blockchain shares a distributed ledger. In this paper, we propose and implement a mobile electronic wallet that can safely store, send and receive cryptocurrencies. The proposed mobile cryptocurrency wallet connects to the network only when the wallet actively is used. Wallet owner manages his or her private key offline, which is advantageous in terms of security. JavaScript based wallet apps were implemented to respectively run on Android and iOS mobile phones. I demonstrate the process of transferring Ethereum cryptocurrency from an account to another account through Ropsten, a test net for Ethereum. Hardware wallets, such as Ledger Nano S, provide a slightly higher level of security, yet have the disadvantages of added burden of carrying additional physical devices and high costs (about 80$).
Kai Lei, Maoyu Du, Liwei Yang, Jin Liu · 7 authors
The last decade has witnessed the explosive growth of digital tokens and cryptocurrencies including Bitcoin, reward programs and various tokens on Ethereum. However, trading these heterogeneous and non-financial digital assets often encounters substantial liquidity barriers due to the lack of interoperable standards, and faces an equilibrium dilemma in pricing strategies with a risk of market disequilibrium. In this sense, we introduce a novel decentralized equilibrium trading mechanism for assets across value systems with a combination of blockchain and economic theories that optimizes storage, equilibrium, and circulation of assets. To demonstrate the practical feasibility of the proposed mechanism, we design, implement, and evaluate an end-to-end prototype system on Ethereum platform with carefully-crafted smart contracts. Our extensive experimental evaluations and the trading simulation suggest that the proposed mechanism settles exchanges and tradings among different assets with equilibrium prices in a decentralized fashion, providing both practical and theoretical foundation for the autonomous equilibrium of asset trading market without human interventions.
Logs are critical data, which can help us to troubleshoot and identify the person in charge of an unexpected accident. Log systems have been widely used for log storage. However, the traditional log system can't prevent the log from being tampered. Centralized servers are more vulnerable to be attacked. Those who have permission to operate records can easily tamper with logs. Blockchain is a disruptive technology in recent years, which has the advantages of decentralization, tamper-proof and traceability. Given its decentralization and tamper-proof properties, the paper proposed a blockchain-based framework for secure log storage. However, the cost of storing big files in the blockchain is very high. Thus, the paper utilized the InterPlanetary File System(IPFS) to store log files instead of a blockchain. Besides, the paper adopted Ethereum blockchain to store the hash of log files and a smart contract to create an index for log files. The solution is not only applicable to log but also other scenarios requiring secure data storage and efficient retrieval.
Healthcare information systems are the next big application area for Blockchain technology. However, straightforward extensions of existing digital cryptocurrency systems such as Bitcoin and Ethereum results in systems that are unsuitable for the challenges posed by healthcare systems. In this paper, we propose an architecture for a blockchain-based healthcare information system in which block validation is performed through collective signatures initiated by a designated leader and executed by a pool of witnesses. Furthermore, we describe a smart-contract based approach that allows data owners to explicitly grant or revoke authorizations for other actors to access healthcare data. All accesses, successful or not, are recorded on the blockchain as separate transactions, thus ensuring transparency and privacy protection.
Most blockchain-based identity authentication systems focus on using blockchain to establish the public key infrastructure (PKI). It can solve the problem of single point of failure and certificate transparency faced by traditional PKI systems, but there are still some problems such as complex certificate management and complex certificate usage process. In this paper, we propose an identity authentication scheme based on blockchain and identity-based cryptography (IBC). The scheme implements a decentralized private key generator (PKG) by deploying the smart contract in Ethereum blockchain, and uses the IBC signature algorithm and challenge-response protocol during the authentication process. Compared with other blockchain-based identity authentication systems, the scheme not only prevents the single point of failure, but also avoids the complex certificate management, has lower system complexity, and resists impersonation attack, man-in-the-middle attack and replay attack.
Cryptography and Data Security
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
Distributed ledgers based on blockchain, such as Bitcoin and Ethereum, are known and used worldwide now. But the existing distributed ledgers are too slow for commercial requirements when compared with centralized systems like Visa. To tackle this issue, many strategies have been put forward, including GHOST, Bitcoin-NG, Sharding, State channel, Plasma, etc. But few of them is focused on the P2P layer, while the P2P layer plays a crucial role as a distributed ledger needs to be updated via block propagation process. We propose an alternative protocol named Ari, which is a P2P optimization for blockchain systems. Ari protocol makes the block propagation graph an intercrossing net rather than a unidirectional tree, thus leading to a great reduction on latency as well as a great expansion on throughput, and the security as well as scalability is still guaranteed.
Benedikt Pittl, Stefan Starflinger, Werner Mach, Erich Schikuta
Amazon's EC2 On-Demand marketspace is the dominant platform for trading Cloud services such as virtual machines. On such platforms consumers and providers do not negotiate with each other. Instead, consumers purchase predefined virtual machines at fixed-prices and so this approach is also termed take-it-or-leave-it approach. In the last years more dynamic platforms emerged such as Amazon's spot marketspace which was relaunched at the end of 2017 - here consumers can bid for virtual machines. The recent efforts of Amazon and other Cloud providers such as VirtuStream show that dynamic trading mechanisms are a promising approach for realizing future Cloud markets. Hence, multi-round bilateral negotiations which are executed autonomously have gained popularity in the scientific community. A key challenge towards the adoption of autonomous multi-round bilateral negotiations is to ensure the integrity and transparency so that the generated agreements are legally biding. In the paper at hand we present an approach which uses a smart contract - called Bazaar-Contract - to ensure integrity and transparency during multi-round bilateral negotiations. Thereby, consumers and providers exchange offers by calling methods of the Bazaar-Contract. Moreover, Cloud referees can use these Bazaar-Contracts in order to manage penalties resulting from poor service quality. In order to prove the technical feasibility of our approach we implemented the Bazaar-Contract using Ethereum and the Inter-Planetary File System. We evaluate the economical feasibility of our approach by considering the gas costs.
Abstract In recent years, with the increase of consumers’ attention to the quality of agricultural products, reliable and reliable traceability technology of agricultural products has been paid more attention. This paper proposed a block-chain traceability system based on smart agriculture with the integration of wireless sensor network. The system has realized the agricultural product traceability system based on Ethereum. After farmers access to the system, data acquisition front-end data storage to block-chain system, the use of block-chain itself has the characteristics of decentralization, tamper-resistant, security encryption, combined with the backend database management and traceability QR code to provide consumers with safe, reliable and real farm products traceability information. Building a holographic database of the tea whole industry chain from farmland to table, adopting the food risk assessment and safety traceability technology based on the hazard factor to design the multi-role, multi-link and multi-factor intelligent management system to realize the efficient control of food quality and safety.
Vasily Derbentsev, Наталія Даценко, Olga Stepanenko, Vitalii Bezkorovainyi
This paper describes the construction of the short-term forecasting model of cryptocurrencies’ prices using machine learning approach. The modified model of Binary Auto Regressive Tree (BART) is adapted from the standard models of regression trees and the data of the time series. BART combines the classic algorithm classification and regression trees (C&RT) and autoregressive models ARIMA. Using the BART model, we made a short-term forecast (from 5 to 30 days) for the 3 most capitalized cryptocurrencies: Bitcoin, Ethereum and Ripple. We found that the proposed approach was more accurate than the ARIMA-ARFIMA models in forecasting cryptocurrencies time series both in the periods of slow rising (falling) and in the periods of transition dynamics (change of trend).
La blockchain propose un système d'enregistrement décentralisé, immuable et transparent. Elle offre un réseau de nœuds sans entité de gouvernance centralisée, ce qui la rend "indéchiffrable" et donc plus sûr que le système d'enregistrement centralisé sur papier ou centralisé telles que les banques. L’approche traditionnelle basée sur l’enregistrement ne fonctionne pas bien avec les relations numériques où les données changent constamment. Contrairement aux canaux traditionnels, régis par des entités centralisées, blockchain offre à ses utilisateurs un certain niveau d'anonymat en leur permettant d'interagir sans divulguer leur identité personnelle et en leur permettant de gagner la confiance sans passer par une entité tierce. En raison des caractéristiques susmentionnées de la blockchain, de plus en plus d'utilisateurs dans le monde sont enclins à effectuer une transaction numérique via blockchain plutôt que par des canaux rudimentaires. Par conséquent, nous devons de toute urgence mieux comprendre comment ces opérations sont gérées par la blockchain et combien de temps cela prend à un nœud du réseau pour confirmer une transaction et l’ajouter au réseau de la blockchain. Dans cette thèse, nous visons à introduire une nouvelle approche qui permettrait d'estimer le temps il faudrait à un nœud de la blockchain Ethereum pour accepter et confirmer une transaction sur un bloc tout en utilisant l'apprentissage automatique. Nous explorons deux des approches les plus fondamentales de l’apprentissage automatique, soit la classification et la régression, afin de déterminer lequel des deux offrirait l’outil le plus efficace pour effectuer la prévision du temps de confirmation dans la blockchain Ethereum. Nous explorons le classificateur Naïve Bayes, le classificateur Random Forest et le classificateur Multilayer Perceptron pour l’approche de la classification. Comme la plupart des transactions sur Ethereum sont confirmées dans le délai de confirmation moyen (15 secondes) de deux confirmations de bloc, nous discutons également des moyens pour résoudre le problème asymétrique du jeu de données rencontré avec l’approche de la classification. Nous visons également à comparer la précision prédictive de deux modèles de régression d’apprentissage automatique, soit le Random Forest Regressor et le Multilayer Perceptron, par rapport à des modèles de régression statistique, précédemment proposés, avec un critère d’évaluation défini, afin de déterminer si l’apprentissage automatique offre un modèle prédictif plus précis que les modèles statistiques conventionnels.
Abstrak Blockchain Technology merupakan sebuah Digital Ledger atau pembukuan digital dari transaksitransaksi virtual, dimana data transaksi tersebut tidak dapat dimodifikasi meskipun telah berpindah dari device ke device lainnya, dengan kata lain setiap data tidak mempunyai Central Authority atau kewenangan pusat untuk mengubah detil data-data tersebut. Setiap data pada teknologi Blockchain disebut Block, dimana setiap Block mengugnakan prinsipprinsip kriptografi untuk mengamankannya. Setiap terciptanya Block pada blockchain. Salah satu platform dari Blockchain ialah Ethereum. Ethereum merupakan platform Blockchain yang menggunakan Smart Contracts untuk dapat menciptakan suatu Block data transaksi. Smart Contract sendiri merupakan protocol yang memfasilitasi, memverifikasi dan mengeksekusi transaksi untuk dicatat ke kontrak yang nantinya dapat diubah ke potongan kode yang dapat disimpan di komputer. Ethereum Blockchain juga sudah dimanfaatkan sebagai model untuk aplikasi-aplikasi seperti yang mayoritas ialah aplikasi web, yang digunakan untuk distribusi data Decentralized, sistem Voting untuk pemilu, dan yang sedang dikembangkan Messenger app. Data-data yang saling berpindah didalam aplikasi-aplikasi yang menggunakan Blockchain sebagai model, tentunya berpindah dengan cara menunggangi transaksi ETH (Cryptocurrency). Setiap data yang berpindah mempunyai Batasan seperti parameter GasPrice, GasLimit, dan Difficulty untuk transaksi berisi data yang dikirim maupun diterima. Untuk menyimpan data ke Block dari Chain Ethereum membutuhkan mata uang digital Ethereum, yang harus dibeli dengan uang asli, untuk itu salah satu alternatif yang dapat diterapkan yaitu pembuatan server Blockchain Ethereum private, dimana setiap transaksi menggunakan mata uang digital Ethereum yang dapat dimodifikasi jumlah saldonya pada Ethereum Wallet ataupun file Genesis.json pada algoritma Ethereum dengan sesuka hati sehingga proses perpindahan data didalam transaksi dapat dilakukan dengan gratis. Kata Kunci : Blockchain, Ethereum, GasPrice, GasLimi, Difficulty, Cryptocurrency, Block Abstract Blockchain Technology is a Digital Ledger or digital bookkeeping of virtual transactions, where the transaction data cannot be modified even though it has moved from device to other device, in other words each data does not have a Central Authority or central authority to change the details of these data . Every data on Blockchain technology is called Block, where each Block uses cryptographic principles to secure it. Every Block is created on the blockchain. One of the platforms of the Blockchain is Ethereum. Ethereum is a Blockchain platform that uses Smart Contracts to be able to create a transaction data block. Smart Contract itself is a protocol that facilitates, verifies and executes transactions to be recorded into contracts that can later be converted to code snippets that can be stored on the computer. Ethereum Blockchain has also been used as a model for applications such as the majority are web applications, which are used for Decentralized data distribution, voting systems for elections, and those that are being developed by the Messenger app. Data that moves between one another in applications that use Blockchain as a model, of course, moves by riding an ETH (Cryptocurrency) transaction. Each moving data has limitations such as GasPrice, GasLimit, and Difficulty parameters for transactions containing sent or received data. To save data to Block from Chain Ethereum requires a digital currency Ethereum, which must be purchased with real money, for that one alternative that can be applied is the creation of a private Blockchain Ethereum server, where each transaction uses the digital currency Ethereum which can be modified Ethereum Wallet or Genesis.json file on the Ethereum algorithm with whatever you want so that the process of transferring data in transactions can be done for free. Key Word : Blockchain, Ethereum, GasPrice, GasLimi, Difficulty, Cryptocurrency, Block
Abstrak Kontrak tertulis mempunyai beberapa kelemahan yaitu kontrak dapat hilang dan rusak, tidak hemat biaya dan salah satu pihak bisa saja melakukan kecurangan. Solusi untuk itu adalah menggunakan smart contract Ethereum. Smart contract Ethereum merupakan protokol komputer yang berfungsi untuk memfasilitasi, memverifikasi, atau menegakakan negoisasi secara digital yang ditulis melalui kode program. Smart contract bekerja tanpa melalui pihak ketiga dan memiliki proses transaksi yang kredibel sehingga tidak bisa dilacak ataupun diubah. Namun teknologi Blockchain tidak cocok untuk menyimpan data dalam jumlah besar dan biaya mahal, maka penulis mengkombinasikan teknologi IPFS pada Ethereum Blockchain. Jadi pada Ethereum Blockchain hanya menyimpan hash file nya saja, kemudian hash file ini dapat dihubungkan dengan file pada IPFS untuk mengaksesnya. Pada penelitian ini dibangun sebuah sistem DApp (Decentralized applications) berbasis web yang menerapkan IPFS pada smart contract Ethereum serta menggunakan metode Network Development Life Cycle (NDLC). Hasil akhir dari penelitian ini adalah pembahasan mengenai integritas data dan Qualitas of Service (QoS) komunikasi antar node IPFS pada smart contract Ethereum sebagai acuan untuk implementasi pada perusahaan. Dengan hasil implementasi tersebut diperoleh bahwa integritas data yang dimiliki oleh IPFS sangat baik dengan memenuhi aspek information security dan memiliki Quality of Service dengan nilai rata – rata throughput sebesar 56.40 Kbps, 65.80 Kbps, dan 66.31 Kbps, untuk nilai rata – rata packet loss sebesar 1.92%, 1.57% dan 0.85%, sedangkan untuk nilai rata – rata delay sebesar 24.78 ms, 25.87 ms dan 20.17 ms dengan nilai rata – rata indeks Quality of Service yaitu 3 yang memenuhi kategori memuaskan berdasarkan standar THIPON. Kata Kunci : Blockchain, Smart Contract, Ethereum, IPFS, Node, Integirtas Data, Quality of Service (QoS) Abstract A written contract has several weaknesses, the contract can be lost and damaged, it is not cost effective and one party can commit fraud. The solution for that is to use the smart contract Ethereum. Smart contract Ethereum is a computer protocol that functions to facilitate, verify, or enforce digital negotiations written through the program code. Smart contract works without going through a third party and has a credible transaction process so that it cannot be tracked or changed. But Blockchain technology is not suitable for storing large amounts of data and expensive costs, so the author combines IPFS technology on Ethereum Blockchain. So the Ethereum Blockchain only stores the hash of the file, then the hash of this file can be connected to the file on IPFS to access it. In this study a web-based DApp (Decentralized applications) system was built that implemented IPFS on the smart contract Ethereum and used the Network Development Life Cycle (NDLC) method. The final result of this study is a discussion of data integrity and Quality of Service (QoS) communication between IPFS nodes on the smart contract Ethereum as a reference for implementation of the company. With the results of the implementation it was found that the data integrity possessed by IPFS was very good by fulfilling aspects of information security and having Quality of Service with average throughput values of 56.40 Kbps, 65.80 Kbps, and 66.31 Kbps, for average packet loss values of 1.92 %, 1.57% and 0.85%, while the average value of delay is 24.78 ms, 25.87 ms and 20.17 ms with the average value of the Quality of Service index which is 3 which satisfies the satisfying category based on THIPON standards. Key Word : Blockchain, Smart Contract, Ethereum, IPFS, Node, Data Integrity, Quality of Service (QoS).
The increasing volatility in pricing and growing potential for profit in digital currency have made predicting the price of cryptocurrency a very attractive research topic. Several studies have already been conducted using various machine-learning models to predict crypto currency prices. This study presented in this paper applied a classic Autoregressive Integrated Moving Average(ARIMA) model to predict the prices of the three major cryptocurrencies âAT Bitcoin, XRP and Ethereum âAT using daily, weekly and monthly time series. The results demonstrated that ARIMA outperforms most other methods in predicting cryptocurrency prices on a daily time series basis in terms of mean absolute error (MAE), mean squared error (MSE) and root mean squared error(RMSE).
Xiaoyu Li, Cheng Su, Yan Xiong, Wenchao Huang · 5 authors
Blockchain is a decentralized cryptocurrency framework which has gained considerable attention in research and many industries. Ethereum is an implementation based on blockchain technology. Ethereum blockchain offers smart contracts, a piece of program codes which can execute and record the transactions in blockchain. Users can use smart contracts to create their own tokens based on ERC-20 standard, and token smart contracts have been used to manage and transfer tokens, carrying millions dollars worth of virtual currencies. However, keeping token smart contracts secure can be difficult. When smart contracts are deployed on Ethereum successfully, they cannot be changed. Due to the openness of Ethereum, both users and attackers can invoke contracts. So errors in smart contracts have led and will lead to a loss. For example, the DAO bug led to a 60 million US dollar loss in June 2016. Therefore, the researches on security of smart contracts are urgently important. In this paper, we use a formal approach to verify smart contracts. We apply formal verification on a concrete smart contract example, BNB contract, which is one of the most popular token contracts. We analyze the contract and discover the two attributes in the contract, one is transfer attribute involving the functions of transferring tokens operations, and the other is owner attribute which involves the authority of contract owner. We verify these two attributes respectively. We model the contract using SAPIC, the applied pi calculus and then verify by Tamarin prover. We specify the processes of modeling and verifying. The results show we cannot find an attack path. The research method reduces the complexity of verifying smart contracts and can be used to analyze complex contracts.
Blockchain Technology Applications and Security
Cryptography and Data Security
Advanced Steganography and Watermarking Techniques
By outsourcing most of storage and computational tasks to full nodes, Ethereum lightweight client is able to run on the resource-limited devices such as mobile phones. In the interactions with the lightweight client, the full node obtains considerable information about Ethereum addresses (Ethereum accounts), transactions, and transaction receipts associated with the lightweight client. This behavior obviously violates user privacy. Currently, there is no solution supporting the lightweight client to efficiently retrieve the account state, related transactions, and transaction receipts from the untrust full node without revealing privacy. In this paper, we propose to use private information retrieval (PIR) to design a privacy-preserving Ethereum lightweight client. Since directly using existing PIR scheme significantly increases communication overhead of the lightweight client, we tailor existing PIR schemes to adapt to the lightweight client, which allows the lightweight client to efficiently retrieve account state and transaction data without leaking sensitive query information. Security and performance analysis show that our scheme is capable of efficiently and privately downloading the data of interest to the lightweight client.
Aug 1, 2019·2019 18th IEEE International Conference On Trust, Security And Privacy In Computing And Communications/13th IEEE International Conference On Big Data Science And Engineering (TrustCom/BigDataSE)
Jiazhuo Lyu, Zoe L. Jiang, Xuan Wang, Zhenhao Nong · 6 authors
E-voting plays a significant role in social activities. The trust of the voting results and the privacy of each voter are always the most important concerns in designing secure e-voting system. In this paper, we design a decentralized trustless e-voting system based on the smart contract. To guarantee the correctness of the voting result, the smart contract on Blockchain is used to provide a trusted public bulletin board and trusted computing environment. To hide the identity of each voter as well as avoid multiple voting, linkable ring signature is used for each voter to group a signing ring. In addition, to make sure that all voters will see the voting result at the same time, or nobody can get it, threshold encryption without trusted third party is used to make secret-key secretly before tally stage. Moreover, the trust (power) of the voting system is separated to all voters. Even though some of them are malicious, the final result will not be influenced. The contract is deployed on the Ethereum private network. Some feasibility and cost analysis on money and time are also provided.
2 source records
Internet Traffic Analysis and Secure E-voting
Advanced Steganography and Watermarking Techniques