24,084 research outputs found
Instantaneous Decentralized Poker
We present efficient protocols for amortized secure multiparty computation
with penalties and secure cash distribution, of which poker is a prime example.
Our protocols have an initial phase where the parties interact with a
cryptocurrency network, that then enables them to interact only among
themselves over the course of playing many poker games in which money changes
hands.
The high efficiency of our protocols is achieved by harnessing the power of
stateful contracts. Compared to the limited expressive power of Bitcoin
scripts, stateful contracts enable richer forms of interaction between standard
secure computation and a cryptocurrency.
We formalize the stateful contract model and the security notions that our
protocols accomplish, and provide proofs using the simulation paradigm.
Moreover, we provide a reference implementation in Ethereum/Solidity for the
stateful contracts that our protocols are based on.
We also adopt our off-chain cash distribution protocols to the special case
of stateful duplex micropayment channels, which are of independent interest. In
comparison to Bitcoin based payment channels, our duplex channel implementation
is more efficient and has additional features
A privacy-preserving, decentralized and functional Bitcoin e-voting protocol
Bitcoin, as a decentralized digital currency, has caused extensive research
interest. There are many studies based on related protocols on Bitcoin,
Bitcoin-based voting protocols also received attention in related literature.
In this paper, we propose a Bitcoin-based decentralized privacy-preserving
voting mechanism. It is assumed that there are n voters and m candidates. The
candidate who obtains t ballots can get x Bitcoins from each voter, namely nx
Bitcoins in total. We use a shuffling mechanism to protect voter's voting
privacy, at the same time, decentralized threshold signatures were used to
guarantee security and assign voting rights. The protocol can achieve
correctness, decentralization and privacy-preservings. By contrast with other
schemes, our protocol has a smaller number of transactions and can achieve a
more functional voting method.Comment: 5 pages;3 figures;Smartworld 201
A fair payment system with online anonymous transfer
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 2007.Includes bibliographical references (p. 26-27).Physical cash can be anonymously transfered. Transferability is a desirable property because it allows for flexible, private commerce where neither the seller nor the buyer must identify themselves to the bank. In some cases, however, anonymity can be abused and lead to problems such as blackmail and money laundering. In 1996, Camenisch, Piveteau, and Stadler introduced the concept of fairness for (non-transferable) ECash, where a trusted authority can revoke the anonymity of certain transactions as needed. To our knowledge, no current ECash system supports both anonymous transfer and fairness. We have designed and implemented such a system. Also, we formally describe a set of desirable properties for ECash systems and prove that our system meets all of these properties under the Strong RSA assumption and the Decisional Diffie-Hellman assumption in the random oracle model. Furthermore, we provide extensions for our system that could allow it to deal with offline payments and micropayments. Our system has been implemented in java. Tests have shown that it performs and scales well, as expected.by Bin D. Vo.M.Eng
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