125 research outputs found
Buying Time: Latency Racing vs. Bidding in Fair Transaction Ordering
We design a practical algorithm for transaction ordering that takes into
account both transaction timestamps and bids. The algorithm guarantees that
users get their transactions published with bounded delay against a bid, while
it extracts a fair value from sophisticated users that have an edge in latency,
by moving expenditure from investment in latency improvement technology to
bidding. The algorithm creates a score from timestamps and bids, and orders
transactions based on the score. We first show that a scoring rule is the only
type of rule that satisfies the independence of latency races. We provide an
economic analysis of the protocol in an environment of private information,
where investment in latency is made ex-ante or interim stages, while bidding
happens at the interim stage where private signals have been observed. The
algorithm is useful for transaction sequencing in rollups or in other
environments where the sequencer has privileged access to order flows
Government Data and the Invisible Hand
If President Barack Obama\u27s new administration really wants to embrace the potential of Internet-enabled government transparency, it should follow a counter-intuitive but ultimately compelling strategy: reduce the federal role in presenting important government information to citizens. Today, government bodies consider their own Web sites to be a higher priority than technical infrastructures that open up their data for others to use. We argue that this understanding is a mistake. It would be preferable for government to understand providing reusable data, rather than providing Web sites, as the core of its online publishing responsibility. During the presidential campaign, all three major candidates indicated that they thought the federal government could make better use of the Internet. Barack Obama\u27s platform went the furthest and explicitly endorsed maling government data available online in universally accessible formats. Hillary Clinton, meanwhile, remarked that she wanted to see much more government information online. John McCain\u27s platform called for a new Office of Electronic Government. But the situation to which these candidates were responding-the wide gap between the exciting uses of Internet technology by private parties, on the one hand, and the government\u27s lagging technical infrastructure, on the other-is not new. A minefield of federal rules and a range of other factors, prevent government Web masters from keeping pace with the evergrowing potential of the Internet
Mixcoin Anonymity for Bitcoin with accountable mixes (Full version)
Abstract. We propose Mixcoin, a protocol to facilitate anonymous payments in Bitcoin and similar cryptocurrencies. We build on the emergent phenomenon of currency mixes, adding an accountability mechanism to expose theft. We demonstrate that incentives of mixes and clients can be aligned to ensure that rational mixes will not steal. Our scheme is efficient and fully compatible with Bitcoin. Against a passive attacker, our scheme provides an anonymity set of all other users mixing coins contemporaneously. This is an interesting new property with no clear analog in better-studied communication mixes. Against active attackers our scheme offers similar anonymity to traditional communication mixes.
Best-first branch-and-bound on a hypercube
The branch-and-bound technique is a common
method for finding exact solutions to difficult problems
in combinatorial optimization. This paper
will discusss issues surrounding implementation of
a particular branch-and-bound algorithm for the
traveling-salesman problem on a hypercube multicomputer.
The natural parallel algorithm is based on a
number of asynchronous processes which interact
through a globally shared list of unfinished work.
In a distributed-memory environment, we must find
a non-centralized version of this shared data structure.
In addition, detecting termination of the computation
is tricky; an algorithm will be presented
which ensures proper termination. Finally, issues
affecting performance will be discussed
Best-first branch-and-bound on a hypercube
The branch-and-bound technique is a common
method for finding exact solutions to difficult problems
in combinatorial optimization. This paper
will discusss issues surrounding implementation of
a particular branch-and-bound algorithm for the
traveling-salesman problem on a hypercube multicomputer.
The natural parallel algorithm is based on a
number of asynchronous processes which interact
through a globally shared list of unfinished work.
In a distributed-memory environment, we must find
a non-centralized version of this shared data structure.
In addition, detecting termination of the computation
is tricky; an algorithm will be presented
which ensures proper termination. Finally, issues
affecting performance will be discussed
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