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Title: Off-Line Karma: A Decentralized Currency for Peer-to-peer and Grid Applications Post by: alkor on March 02, 2011, 04:40:16 PM Has anybody looked at the following article published in Applied Cryptography and Network Security?
Off-Line Karma: A Decentralized Currency for Peer-to-peer and Grid Applications Flavio D. Garcia and Jaap-Henk Hoepman (http://www.springerlink.com/content/g6v6p3ucc8x0wk64) Abstract: Quote Peer-to-peer (P2P) and grid systems allow their users to exchange information and share resources, with little centralised or hierarchical control, instead relying on the fairness of the users to make roughly as much resources available as they use. To enforce this balance, some kind of currency or barter (called karma) is needed that must be exchanged for resources thus limiting abuse. We present a completely decentralised, off-line karma implementation for P2P and grid systems, that detects double-spending and other types of fraud under varying adversarial scenarios. The system is based on tracing the spending pattern of coins, and distributing the normally central role of a bank over a predetermined, but random, selection of nodes. The system is designed to allow nodes to join and leave the system at arbitrary times. Keywords: Decentralised systems, micropayments, free-riding, security, grid, peer-to-peer. Is this related to Bitcoin in any way? Or is it a completely different concept of an electronic currency? Title: Re: Off-Line Karma: A Decentralized Currency for Peer-to-peer and Grid Applications Post by: alkor on March 02, 2011, 04:46:50 PM Does anybody have access to the full PDF by the way? I would be interested to read about how they propose to implement the concept of a time-stamp server in a decentralized manner.
EDIT: Nevermind, a simple google search was enough to find a pdf www.hashcash.org/papers/offline-karma.pdf Title: Re: Off-Line Karma: A Decentralized Currency for Peer-to-peer and Grid Applications Post by: Cusipzzz on March 02, 2011, 05:13:18 PM I stopped reading at identifying nodes w/a Certificate Authority. lol.
Title: Re: Off-Line Karma: A Decentralized Currency for Peer-to-peer and Grid Applications Post by: Garrett Burgwardt on March 02, 2011, 10:20:28 PM Sounds a bit like Whuffie (http://en.wikipedia.org/wiki/Whuffie)
Title: Re: Off-Line Karma: A Decentralized Currency for Peer-to-peer and Grid Applications Post by: Mike Hearn on March 03, 2011, 02:32:00 PM Quote We also assume that the overlay network is capable of safely distribut- ing a blacklist of banned users. Whenever a user detects fraud and has a proof of that, he can submit it to the overlay network which makes this information available to every user. How to implement the distribution of blacklist securely is beyond the scope of this paper. Ah. That seems rather the nub of the problem for a decentralized system that relies on punishing or shunning fraudulent members. They don't seem to be aware of BitCoin. Otherwise they would have mentioned it at the start. The key difference is they focus on the offline case whereas Satoshi really does not. Their scheme for handling double spends is to compare multiple competing histories of the coin from time to time and then simply blacklist whoever caused the fork (eg the coin owner themselves). So this is not an anonymous scheme as you need some robust way to blacklist people. More problematically by the time the double spending is found, it cannot be corrected. It's not like BitCoin where one of the spends wins and the other loses. Both merchants potentially lose. BitCoin seems like a better design to me. But they may disagree. Perhaps somebody should point them to Satoshis paper and this forum, it'd be interesting to see their thoughts. Title: Re: Off-Line Karma: A Decentralized Currency for Peer-to-peer and Grid Applications Post by: Cryptoman on March 03, 2011, 03:23:21 PM They don't seem to be aware of BitCoin. Otherwise they would have mentioned it at the start. The key difference is they focus on the offline case whereas Satoshi really does not. The paper is from 2005. I wonder if Satoshi knew about it? Title: Re: Off-Line Karma: A Decentralized Currency for Peer-to-peer and Grid Applications Post by: Mike Hearn on March 03, 2011, 06:07:00 PM Oops, good point. I wish academic papers provided dates at the start along with contact details.
Title: Re: Off-Line Karma: A Decentralized Currency for Peer-to-peer and Grid Applications Post by: ribuck on March 03, 2011, 06:34:20 PM The paper is from 2005. I wonder if Satoshi knew about it? It's not one of the references listed at the end of Satoshi's paper (http://www.bitcoin.org/bitcoin.pdf). |