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EPFL Researchers Invent Low-Cost Alternative to Bitcoin:
The cryptocurrency Bitcoin is limited by its astronomical electricity consumption and outsized carbon footprint. A nearly zero-energy alternative sounds too good to be true, but as School of Computer and Communication Sciences (IC) Professor Rachid Guerraoui explains, it all comes down to our understanding of what makes transactions secure.
To explain why the system developed in his Distributed Computing Lab (DCL) represents a paradigm shift in how we think about cryptocurrencies -- and about digital trust in general -- Professor Rachid Guerraoui uses a legal metaphor: all players in this new system are "innocent until proven guilty."
This is in contrast to the traditional Bitcoin model first described in 2008 by Satoshi Nakamoto, which relies on solving a difficult problem called "consensus" to guarantee the security of transactions. In this model, everyone in a distributed system must agree on the validity of all transactions to prevent malicious players from cheating -- for example, by spending the same digital tokens twice (double-spending). In order to prove their honesty and achieve consensus, players must execute complex -- and energy-intensive -- computing tasks that are then verified by the other players.
But in their new system, Guerraoui and his colleagues flip the assumption that all players are potential cheaters on its head.
What do you guys think? Will this replace Bitcoin?
(Score: 2) by JoeMerchant on Friday October 04 2019, @03:08PM (5 children)
The Secret Service does, in fact, monitor overseas use of US currency, even where they lack jurisdiction. Do I believe that they achieve the 1:10,000 counterfeit to genuine bill ration they claim - maybe domestically where it can be somewhat independently verified, but not at all internationally.
Bigger exploits, because the actual circulating value of US dollars - being exchanged for actual goods and services - exceeds BTC by several orders of magnitude?
My "problem" with proof of work isn't so much that it is exploitable, and has been verifiably exploited for millions of dollars in "coin value" multiple times, the problem is the absolutely massive quantity of energy that is being expended to attempt to maintain this imperfect, and unscalable, system.
For all your hubbub, the 50+% exploit is counterfeiting of (any) proof of work coin, and like all counterfeiting it works until it is detected. With "lightning fast" transactions, the counterfeit blockchains have been able to convince others to give them massive amounts of value before they are detected.
Україна досі не є частиною Росії Слава Україні🌻 https://news.stanford.edu/2023/02/17/will-russia-ukraine-war-end
(Score: 1) by khallow on Saturday October 05 2019, @02:44AM (4 children)
What is the point of your disbelief here? You dropped a bunch of links for some reason.
(Score: 2) by JoeMerchant on Sunday October 06 2019, @09:09PM (3 children)
If you sniff around enough the press would seem to contradict itself - frequently. Secret Service states 60% of all counterfeit currency comes from country X, 30% from country Y in another story, 20% from country Z in a third - oh, wait, maybe it shifts over time... well, does it shift enough to also account for 40% coming from country W? They do stick pretty steadfast to the 1/10,000 bill story domestically and overseas - but maybe that's true with the $20 being the most commonly counterfeited domestically and the $100 internationally? More likely it's just an easy soundbite to train everyone to for chance interactions with the press.
Україна досі не є частиною Росії Слава Україні🌻 https://news.stanford.edu/2023/02/17/will-russia-ukraine-war-end
(Score: 1) by khallow on Monday October 07 2019, @03:19AM (2 children)
(Score: 2) by JoeMerchant on Monday October 07 2019, @12:08PM (1 child)
Can "we"? Any examples of better than 50% "security" in practice yet? It's been 10 years.
Україна досі не є частиною Росії Слава Україні🌻 https://news.stanford.edu/2023/02/17/will-russia-ukraine-war-end
(Score: 1) by khallow on Monday October 07 2019, @01:13PM
Much of the problem is selective communication, such as in the Byzantine generals [microsoft.com] problem where N generals decide by consensus whether to attack or retreat, but traitors can selectively lie, so that some receive a concensus of attack and some retreat (the idea being that a mixture of some parties attacking and some retreating are worse). The linked paper describes an optimal solution for the basic problem which allows for successful decision making even when there's m traitors among 3m+1 generals. So more than 2/3 of generals need to be honest in order for this particular scheme to work.
Now, suppose those generals then report all the communications they receive with incontrovertible evidence that the messages are correct (say a one-time hash signature that can only be generated by a secret held by the general generating the message), then suddenly the game changes. Any general who has submitted two different messages (which would have to be correctly signed in the first place or they would be rejected) to two honest generals (the only situation where such treachery would be at all useful), is now outed as a traitor. It doesn't matter what sort of games the traitor generals play at that point - they can only expose more traitors, they can't hide traitors nor falsely convict honest generals.
In practice, this is computationally hard since every communication step then becomes the square of the number of participants in the market which is why it's not done presently. But you can do more such checking than present to increase the threshold needed for such "byzantine faults" [wikipedia.org] of deception to succeed.