Permacoin: Repurposing bitcoin work for data preservation

Permacoin: Repurposing Bitcoin Work for Data Preservation

Permacoin: Repurposing Bitcoin Work for Data Preservation

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Permacoin: Repurposing Bitcoin Work for Data Preservation

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Permacoin: Repurposing Bitcoin Work for Data Preservation (Microsoft Research)

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"Permacoin: Repurposing Bitcoin Work for Data Preservation"

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Microsoft Permacoin: Repurposing Bitcoin Work for Data Preservation

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Bobtail: A Proof-of-Work Target that Minimizes Blockchain Mining Variance

Date: 2017-10-19
Author(s): George Bissias, Brian Neil Levine

Link to Paper

Blockchain systems are designed to produce blocks at a constant average rate. The most popular systems currently employ a Proof of Work (PoW) algorithm as a means of creating these blocks. Bitcoin produces, on average, one block every 10 minutes. An unfortunate limitation of all deployed PoW blockchain systems is that the time between blocks has high variance. For example, 5% of the time, Bitcoin's inter-block time is at least 40 minutes. This variance impedes the consistent flow of validated transactions through the system. We propose an alternative process for PoW-based block discovery that results in an inter-block time with significantly lower variance. Our algorithm, called Bobtail, generalizes the current algorithm by comparing the mean of the k lowest order statistics to a target. We show that the variance of inter-block times decreases as k increases. If our approach were applied to Bitcoin, about 80% of blocks would be found within 7 to 12 minutes, and nearly every block would be found within 5 to 18 minutes; the average inter-block time would remain at 10 minutes. Further, we show that low-variance mining significantly thwarts doublespend and selfish mining attacks. For Bitcoin and Ethereum currently (k=1), an attacker with 40% of the mining power will succeed with 30% probability when the merchant sets up an embargo of 8 blocks; however, when k>=20, the probability of success falls to less than 1%. Similarly, for Bitcoin and Ethereum currently, a selfish miner with 40% of the mining power will claim about 66% of blocks; however, when k>=5, the same miner will find that selfish mining is less successful than honest mining. The cost of our approach is a larger block header.

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The Proof is in the Pudding: Proofs of Work for Solving Discrete Logarithms

Cryptology ePrint Archive: Report 2018/939
Date: 2018-10-05
Author(s): Marcella Hastings, Nadia Heninger, Eric Wustrow

Link to Paper

We propose a proof of work protocol that computes the discrete logarithm of an element in a cyclic group. Individual provers generating proofs of work perform a distributed version of the Pollard rho algorithm. Such a protocol could capture the computational power expended to construct proof-of-work-based blockchains for a more useful purpose, as well as incentivize advances in hardware, software, or algorithms for an important cryptographic problem. We describe our proposed construction and elaborate on challenges and potential trade-offs that arise in designing a practical proof of work.

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Merged Mining: Analysis of Effects and Implications

Date: 2017-08-24
Author(s): Alexei Zamyatin, Edgar Weippl

Link to Paper

Merged mining refers to the concept of mining more than one cryptocurrency without necessitating additional proof-of-work effort. Merged mining was introduced in 2011 as a boostrapping mechanism for new cryptocurrencies and countermeasures against the fragmentation of mining power across competing systems. Although merged mining has already been adopted by a number of cryptocurrencies, to this date little is known about the effects and implications.
In this thesis, we shed light on this topic area by performing a comprehensive analysis of merged mining in practice. As part of this analysis, we present a block attribution scheme for mining pools to assist in the evaluation of mining centralization. Our findings disclose that mining pools in merge-mined cryptocurrencies have operated at the edge of, and even beyond, the security guarantees offered by the underlying Nakamoto consensus for extended periods. We discuss the implications and security considerations for these cryptocurrencies and the mining ecosystem as a whole, and link our findings to the intended effects of merged mining.

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EtherCasts - YouTube

Permacoin: Repurposing Bitcoin Work for Data Preservation Andrew Miller1, Ari Juels2, Elaine Shi1, Bryan Parno3 and Jonathan Katz1 1University of Maryland 2Cornell Tech (Jacobs) 3Microsoft Research Abstract Bitcoin is widely regarded as the first broadly successful e-cash system. An oft-cited concern, though, is that mining Permacoin: Repurposing Bitcoin Work for Data Preservation Andrew Miller1 , Ari Juels2 , Elaine Shi1 , Bryan Parno3 and Jonathan Katz1 1. University of Maryland Cornell Tech (Jacobs) 3 Microsoft Permacoin: Repurposing Bitcoin Work for Data Preservation Abstract: Bit coin is widely regarded as the first broadly successful e-cash system. An oft-cited concern, though, is that mining Bit coins wastes computational resources. Indeed, Bit coin's underlying mining mechanism, which we call a scratch-off puzzle (SOP), involves continuously @MISC{Miller_permacoin:repurposing, author = {Andrew Miller and Ari Juels and Elaine Shi and Bryan Parno and Jonathan Katz}, title = {Permacoin: Repurposing Bitcoin Work for Data Preservation}, year = {}} Share. OpenURL . Abstract. Bitcoin is widely regarded as the first broadly successful e-cash system. An oft-cited concern, though, is that Permacoin: Repurposing Bitcoin Work for Data Preservation. use the following search parameters to narrow your results: subreddit:subreddit find submissions in "subreddit"

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EtherCasts - YouTube

Permacoin: Repurposing Bitcoin Work for Data Preservation - Duration: 33 minutes. 7,402 views; 5 years ago; Loading... Load more Language: English Location: United States Andrew Miller speaks on Permacoin, a new security technique for cryptocurrencies that allows distributed storage of petabytes of data. ... Permacoin: Repurposing Bitcoin Work for Data Preservation ...

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