A Survey of Attacks on Ethereum Smart Contracts SoK
22 Apr 2017-Vol. 10204, pp 164-186
TL;DR: This work analyses the security vulnerabilities of Ethereum smart contracts, providing a taxonomy of common programming pitfalls which may lead to vulnerabilities, and shows a series of attacks which exploit these vulnerabilities, allowing an adversary to steal money or cause other damage.
Abstract: Smart contracts are computer programs that can be correctly executed by a network of mutually distrusting nodes, without the need of an external trusted authority. Since smart contracts handle and transfer assets of considerable value, besides their correct execution it is also crucial that their implementation is secure against attacks which aim at stealing or tampering the assets. We study this problem in Ethereum, the most well-known and used framework for smart contracts so far. We analyse the security vulnerabilities of Ethereum smart contracts, providing a taxonomy of common programming pitfalls which may lead to vulnerabilities. We show a series of attacks which exploit these vulnerabilities, allowing an adversary to steal money or cause other damage.
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10 Dec 2018
TL;DR: The experiment proves that the Bit-slice based SM4 is more efficient than the original version and increases the encryption and decryption speed of the message by an average of 80%–120%, compared with the original approach.
Abstract: The SM4 block cipher algorithm used in IEEE 802.11i standard is released by the China National Cryptographic Authority and is one of the most important symmetric cryptographic algorithms in China. However, whether in the round encryption or key expansion phase of the SM4 algorithm, a large number of bit operations on the registers (e.g., circular shifting) are required. These operations are not effective to encryption in scenarios with large-scale data. In traditional implementations of SM4, different operands are assigned to different words and are processed serially, which can bring redundant operations in the process of encryption and decryption. Bit-slice technology places the same bit of multiple operands into one word, which facilitates bit-level operations in parallel. Bit-slice is actually a single instruction parallel processing technology for data, hence it can be accelerated by the CPU’s multimedia instructions. In this paper, we propose a fast implementation of the SM4 algorithm using bit-slice techniques. The experiment proves that the Bit-slice based SM4 is more efficient than the original version. It increases the encryption and decryption speed of the message by an average of 80%–120%, compared with the original approach.
11 citations
Posted Content•
TL;DR: A formalisation of Solidity and the Ethereum blockchain using the Solid language and its blockchain is presented; a Solid program is obtained by explicating/desugaring a Solidity program and some abstractions are made that over-approximate the way in which Solidity/Ethereum behave.
Abstract: The exploitation of smart-contract vulnerabilities can have catastrophic consequences such as the loss of millions of pounds worth of crypto assets. Formal verification can be a useful tool in identifying vulnerabilities and proving that they have been fixed. In this paper, we present a formalisation of Solidity and the Ethereum blockchain using the Solid language and its blockchain; a Solid program is obtained by explicating/desugaring a Solidity program. We make some abstractions that over-approximate the way in which Solidity/Ethereum behave. Based on this formalisation, we create Solidifier: a bounded model checker for Solidity. It translates Solid into Boogie, an intermediate verification language, that is later verified using Corral, a bounded model checker for Boogie. Unlike much of the work in this area, we do not try to find specific behavioural/code patterns that might lead to vulnerabilities. Instead, we provide a tool to find errors/bad states, i.e. program states that do not conform with the intent of the developer. Such a bad state, be it a vulnerability or not, might be reached through the execution of specific known code patterns or through behaviours that have not been anticipated.
11 citations
Cites background from "A Survey of Attacks on Ethereum Sma..."
...When exploited, these vulnerabilities can lead to catastrophic effects such as the loss of vast sums of money [15]....
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01 Sep 2019
TL;DR: This paper discusses the problem of data quality in blockchain applications at three levels of abstraction, i.e., conceptual, logical and physical; special attention at this level is paid to Ethereum and Solidity.
Abstract: This paper discusses the problem of data quality in blockchain applications at three levels of abstraction, i.e., conceptual, logical and physical. Conceptually, it makes explicit the need for information of typical data quality metrics for their online assessment. Logically, it analyzes how the adoption of blockchain technology affects the availability of the data needed for quality assessment. Physically, it identifies a set of implementation options that take into account the information needs of metrics and the restrictions by the technology; special attention at this level is paid to Ethereum and Solidity. Two case studies put the identified patterns and abstractions into context and showcase their importance in real-world distributed applications and processes.
11 citations
Cites methods from "A Survey of Attacks on Ethereum Sma..."
...[1] survey smart contracts deployed in the Ethereum blockchain, classifying their code vulnerabilities....
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TL;DR: In this article, the authors proposed a software tool that can easily perform comparative studies by adding existing/new countermeasures and labeled smart contract codes, which helps to identify the most effective countermeasures for each type of vulnerability.
Abstract: Blockchain technology, which provides digital security in a distributed manner, has evolved into a key technology that can build efficient and reliable decentralized applications (called DApps) beyond the function of cryptocurrency. The characteristics of blockchain such as immutability and openness, however, have made DApps more vulnerable to various security risks, and thus it has become of great significance to validate the integrity of DApps before they actually operate upon blockchain. Recently, research on vulnerability in smart contracts (a building block of DApps) has been actively conducted, and various vulnerabilities and their countermeasures were reported. However, the effectiveness of such countermeasures has not been studied well, and no appropriate methods have been proposed to evaluate them. In this paper, we propose a software tool that can easily perform comparative studies by adding existing/new countermeasures and labeled smart contract codes. The proposed tool demonstrates verification performance using various statistical indicators, which helps to identify the most effective countermeasures for each type of vulnerability. Using the proposed tool, we evaluated state-of-the-art countermeasures with 237 labeled benchmark codes. The results indicate that for certain types of vulnerabilities, some countermeasures show evenly good performance scores on various metrics. However, it is also observed that countermeasures that detect the largest number of vulnerable codes typically generate much more false positives, resulting in very low precision and accuracy. Consequently, under given constraints, different countermeasures may be recommended for detecting vulnerabilities of interest. We believe that the proposed tool could effectively be utilized for a future verification study of smart contract applications and contribute to the development of practical and secure smart contract applications.
11 citations
25 Jun 2018
TL;DR: This tutorial presentation first study the original Bitcoin design, as well as Ethereum and Hyperledger, and reflect on their design from an academic perspective, and concludes with a walkthrough showing the process of developing a decentralized application using a popular Smart Contract language (Solidity) for the blockchain platform of Ethereum.
Abstract: Popularly known for powering cryptocurrencies such as Bitcoin and Ethereum, blockchains is seen as a disruptive technology capable of impacting a wide variety of domains, ranging from finance to governance, by offering superior security, reliability, and transparency in a decentralized manner. In this tutorial presentation, we first study the original Bitcoin design, as well as Ethereum and Hyperledger, and reflect on their design from an academic perspective. We provide an overview of potential applications and associated research challenges, as well as a survey of ongoing research projects. We mention opportunities blockchain creates for event-based systems. Finally, we conclude with a walkthrough showing the process of developing a decentralized application (DSApp), using a popular Smart Contract language (Solidity) for the blockchain platform of Ethereum.
11 citations
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24 Oct 2016
TL;DR: This paper investigates the security of running smart contracts based on Ethereum in an open distributed network like those of cryptocurrencies, and proposes ways to enhance the operational semantics of Ethereum to make contracts less vulnerable.
Abstract: Cryptocurrencies record transactions in a decentralized data structure called a blockchain. Two of the most popular cryptocurrencies, Bitcoin and Ethereum, support the feature to encode rules or scripts for processing transactions. This feature has evolved to give practical shape to the ideas of smart contracts, or full-fledged programs that are run on blockchains. Recently, Ethereum's smart contract system has seen steady adoption, supporting tens of thousands of contracts, holding millions dollars worth of virtual coins. In this paper, we investigate the security of running smart contracts based on Ethereum in an open distributed network like those of cryptocurrencies. We introduce several new security problems in which an adversary can manipulate smart contract execution to gain profit. These bugs suggest subtle gaps in the understanding of the distributed semantics of the underlying platform. As a refinement, we propose ways to enhance the operational semantics of Ethereum to make contracts less vulnerable. For developers writing contracts for the existing Ethereum system, we build a symbolic execution tool called Oyente to find potential security bugs. Among 19, 336 existing Ethereum contracts, Oyente flags 8, 833 of them as vulnerable, including the TheDAO bug which led to a 60 million US dollar loss in June 2016. We also discuss the severity of other attacks for several case studies which have source code available and confirm the attacks (which target only our accounts) in the main Ethereum network.
1,232 citations