1,896 research outputs found
An Alternative Paradigm for Developing and Pricing Storage on Smart Contract Platforms
Smart contract platforms facilitate the development of important and diverse
distributed applications in a simple manner. This simplicity stems from the
inherent utility of employing the state of smart contracts to store, query and
verify the validity of application data. In Ethereum, data storage incurs an
underpriced, non-recurring, predefined fee. Furthermore, as there is no
incentive for freeing or minimizing the state of smart contracts, Ethereum is
faced with a tragedy of the commons problem with regards to its monotonically
increasing state. This issue, if left unchecked, may lead to centralization and
directly impact Ethereum's security and longevity. In this work, we introduce
an alternative paradigm for developing smart contracts in which their state is
of constant size and facilitates the verification of application data that are
stored to and queried from an external, potentially unreliable, storage
network. This approach is relevant for a wide range of applications, such as
any key-value store. We evaluate our approach by adapting the most widely
deployed standard for fungible tokens, i.e., the ERC20 token standard. We show
that Ethereum's current cost model penalizes our approach, even though it
minimizes the overhead to Ethereum's state and aligns well with Ethereum's
future. We address Ethereum's monotonically increasing state in a two-fold
manner. First, we introduce recurring fees that are proportional to the state
of smart contracts and adjustable by the miners that maintain the network.
Second, we propose a scheme where the cost of storage-related operations
reflects the effort that miners have to expend to execute them. Lastly, we show
that under such a pricing scheme that encourages economy in the state consumed
by smart contracts, our ERC20 token adaptation reduces the incurred transaction
fees by up to an order of magnitude.Comment: 6 pages, 2 figures, DAPPCON 201
A Blockchain-based Decentralized Electronic Marketplace for Computing Resources
AbstractWe propose a framework for building a decentralized electronic marketplace for computing resources. The idea is that anyone with spare capacities can offer them on this marketplace, opening up the cloud computing market to smaller players, thus creating a more competitive environment compared to today's market consisting of a few large providers. Trust is a crucial component in making an anonymized decentralized marketplace a reality. We develop protocols that enable participants to interact with each other in a fair way and show how these protocols can be implemented using smart contracts and blockchains. We discuss and evaluate our framework not only from a technical point of view, but also look at the wider context in terms of fair interactions and legal implications
Smarter Data Availability Checks in the Cloud: Proof of Storage via Blockchain
Cloud computing offers clients flexible and cost-effective resources. Nevertheless, past incidents indicate that the cloud may misbehave by exposing or tampering with clients' data. Therefore, it is vital for clients to protect the confidentiality and integrity of their outsourced data. To address these issues, researchers proposed cryptographic protocols called “proof of storage” that let a client efficiently verify the integrity or availability of its data stored in a remote cloud server. However, in these schemes, the client either has to be online to perform the verification itself or has to delegate the verification to a fully trusted auditor. In this chapter, a new scheme is proposed that lets the client distribute its data replicas among multiple cloud servers to achieve high availability without the need for the client to be online for the verification and without a trusted auditor's involvement. The new scheme is mainly based on blockchain smart contracts. It illustrates how a combination of cloud computing and blockchain technology can resolve real-world problems
Betrayal, Distrust, and Rationality: Smart Counter-Collusion Contracts for Verifiable Cloud Computing
Cloud computing has become an irreversible trend. Together comes the pressing
need for verifiability, to assure the client the correctness of computation
outsourced to the cloud. Existing verifiable computation techniques all have a
high overhead, thus if being deployed in the clouds, would render cloud
computing more expensive than the on-premises counterpart. To achieve
verifiability at a reasonable cost, we leverage game theory and propose a smart
contract based solution. In a nutshell, a client lets two clouds compute the
same task, and uses smart contracts to stimulate tension, betrayal and distrust
between the clouds, so that rational clouds will not collude and cheat. In the
absence of collusion, verification of correctness can be done easily by
crosschecking the results from the two clouds. We provide a formal analysis of
the games induced by the contracts, and prove that the contracts will be
effective under certain reasonable assumptions. By resorting to game theory and
smart contracts, we are able to avoid heavy cryptographic protocols. The client
only needs to pay two clouds to compute in the clear, and a small transaction
fee to use the smart contracts. We also conducted a feasibility study that
involves implementing the contracts in Solidity and running them on the
official Ethereum network.Comment: Published in ACM CCS 2017, this is the full version with all
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