14 research outputs found
Bribes to Miners: Evidence from Ethereum
Though blockchain aims to alleviate bribing attacks, users can collude with
miners by directly sending bribes. This paper focuses on empirical evidence of
bribes to miners, and the detected behaviour implies that mining power could be
exploited. By scanning transactions on Ethereum, transactions for potential
direct bribes are filtered, and we find that the potential bribers and bribees
are centralized in a small group. After constructing proxies of active level of
potential bribing, we find that potential bribes can affect the status of
Ethereum and other mainstream blockchains, and network adoption of blockchain
can be influenced as well. Besides, direct bribes can be related to stock
markets, e.g., S&P 500 and Nasdaq
LNCS.
Smart contracts are computer programs that are executed by a network of mutually distrusting agents, without the need of an external trusted authority. Smart contracts handle and transfer assets of considerable value (in the form of crypto-currency like Bitcoin). Hence, it is crucial that their implementation is bug-free. We identify the utility (or expected payoff) of interacting with such smart contracts as the basic and canonical quantitative property for such contracts. We present a framework for such quantitative analysis of smart contracts. Such a formal framework poses new and novel research challenges in programming languages, as it requires modeling of game-theoretic aspects to analyze incentives for deviation from honest behavior and modeling utilities which are not specified as standard temporal properties such as safety and termination. While game-theoretic incentives have been analyzed in the security community, their analysis has been restricted to the very special case of stateless games. However, to analyze smart contracts, stateful analysis is required as it must account for the different program states of the protocol. Our main contributions are as follows: we present (i)~a simplified programming language for smart contracts; (ii)~an automatic translation of the programs to state-based games; (iii)~an abstraction-refinement approach to solve such games; and (iv)~experimental results on real-world-inspired smart contracts
Smart contracts for bribing miners
We present three smart contracts that allow a briber to fairly
exchange bribes to miners who pursue a mining strategy benefiting the
briber. The first contract, CensorshipCon, highlights that Ethereum’s
uncle block reward policy can directly subsidise the cost of bribing miners.
The second contract, HistoryRevisionCon, rewards miners via an
in-band payment for reversing transactions or enforcing a new state of
another contract. The third contract, GoldfingerCon, rewards miners
in one cryptocurrency for reducing the utility of another cryptocurrency.
This work is motivated by the need to understand the extent
to which smart contracts can impact the incentive mechanisms involved
in Nakamoto-style consensus protocols
Musketeer: Incentive-Compatible Rebalancing for Payment Channel Networks
In this work, we revisit the severely limited throughput problem of cryptocurrencies and propose a novel rebalancing approach for Payment Channel Networks (PCNs). PCNs are a popular solution for increasing the blockchain throughput, however, their benefit depends on the overall users’ liquidity. Rebalancing mechanisms are the state-of-the-art approach to maintaining high liquidity in PCNs. However, existing opt-in rebalancing mechanisms exclude users that may assist in rebalancing for small service fees, leading to suboptimal solutions and under-utilization of the PCNs’ bounded liquidity.
We introduce the first rebalancing approach for PCNs that includes all users, following an “all for one and one for all” design philosophy that yields optimal throughput. The proposed approach introduces a double-auction rebalancing problem, which we term Musketeer, where users can participate as buyers (paying fees to rebalance) or sellers (charging fees to route transactions). The desired properties tailored to the unique characteristics of PCNs are formally defined, including the novel property of cyclic budget balance that is a stronger variation of strong budget balance. Basic results derived from auction theory, including an impossibility and multiple mechanisms that either achieve all desiderata under a relaxed model or sacrifice one of the properties, are presented. We also propose a novel mechanism that leverages time delays as an additional cost to users. This mechanism is provably truthful, cyclic budget balanced, individually rational, and economic efficient
but only with respect to liquidity