170,074 research outputs found
Contracts Ex Machina
Smart contracts are self-executing digital transactions using decentralized cryptographic mechanisms for enforcement. They were theorized more than twenty years ago, but the recent development of Bitcoin and blockchain technologies has rekindled excitement about their potential among technologists and industry. Startup companies and major enterprises alike are now developing smart contract solutions for an array of markets, purporting to offer a digital bypass around traditional contract law. For legal scholars, smart contracts pose a significant question: Do smart contracts offer a superior solution to the problems that contract law addresses? In this article, we aim to understand both the potential and the limitations of smart contracts. We conclude that smart contracts offer novel possibilities, may significantly alter the commercial world, and will demand new legal responses. But smart contracts will not displace contract law. Understanding why not brings into focus the essential role of contract law as a remedial institution. In this way, smart contracts actually illuminate the role of contract law more than they obviate it
An empirical analysis of smart contracts: platforms, applications, and design patterns
Smart contracts are computer programs that can be consistently executed by a
network of mutually distrusting nodes, without the arbitration of a trusted
authority. Because of their resilience to tampering, smart contracts are
appealing in many scenarios, especially in those which require transfers of
money to respect certain agreed rules (like in financial services and in
games). Over the last few years many platforms for smart contracts have been
proposed, and some of them have been actually implemented and used. We study
how the notion of smart contract is interpreted in some of these platforms.
Focussing on the two most widespread ones, Bitcoin and Ethereum, we quantify
the usage of smart contracts in relation to their application domain. We also
analyse the most common programming patterns in Ethereum, where the source code
of smart contracts is available.Comment: WTSC 201
The Art of The Scam: Demystifying Honeypots in Ethereum Smart Contracts
Modern blockchains, such as Ethereum, enable the execution of so-called smart
contracts - programs that are executed across a decentralised network of nodes.
As smart contracts become more popular and carry more value, they become more
of an interesting target for attackers. In the past few years, several smart
contracts have been exploited by attackers. However, a new trend towards a more
proactive approach seems to be on the rise, where attackers do not search for
vulnerable contracts anymore. Instead, they try to lure their victims into
traps by deploying seemingly vulnerable contracts that contain hidden traps.
This new type of contracts is commonly referred to as honeypots. In this paper,
we present the first systematic analysis of honeypot smart contracts, by
investigating their prevalence, behaviour and impact on the Ethereum
blockchain. We develop a taxonomy of honeypot techniques and use this to build
HoneyBadger - a tool that employs symbolic execution and well defined
heuristics to expose honeypots. We perform a large-scale analysis on more than
2 million smart contracts and show that our tool not only achieves high
precision, but is also highly efficient. We identify 690 honeypot smart
contracts as well as 240 victims in the wild, with an accumulated profit of
more than $90,000 for the honeypot creators. Our manual validation shows that
87% of the reported contracts are indeed honeypots
- …