emin-gun-sirer

6 ms·

1.
by emin-gun-sirer 11y ago
>The only special power of a 50% miner is to consistently resolve double-spend attempts in its favor. No, this post, and the handy table inside, explains the various attacks possible at different percentages of the hash rate: http:&#x2F
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by emin-gun-sirer 11y ago
Miner consolidation is a long-standing problem with Bitcoin itself. When Ittay and I discovered selfish mining [1], we were quite worried about the size of mining pools at the time. Even though we also came up for a fix against selfish mini
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by emin-gun-sirer 11y ago
All good questions, all of which are answered in the white paper. An "elected leader" is essentially the same thing as a miner that mines a block in Bitcoin. Miners can mine empty blocks in Bitcoin. This is OK, as others will step
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by emin-gun-sirer 11y ago
This sounds like a use case for Macaroons [1]. A primer and a public implementation can be found here [2]. There's also a JavaScript implementation [3]. [1] http://research.google.com/pubs/pub41892.html [2] http:
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by emin-gun-sirer 11y ago
Thanks, indeed, there are many alternative NTP servers [1]. But I believe time.nist.gov is the default time server during Ubuntu installation, so there are many hosts that depend entirely on time.nist.gov. [1] http://www.pool.ntp
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Can't resolve time.nist.gov
1 points by emin-gun-sirer 11y ago|2 comments
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by emin-gun-sirer 12y ago
HyperDex provides scalable and high-performance transactions. While it is strongly (not eventually) consistent, the underlying technique we use to achieve atomicity of transactions is reminiscent of this approach. On a related note, our exp
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by emin-gun-sirer 12y ago
>For the record, I appreciate your technical critiques! But you seem to take a perverse delight in being the critic. Ok, so you enjoy the technical content but disagree with the tone [1]? I can understand that. I genuinely feel sorry I d
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by emin-gun-sirer 12y ago
Yes, it's an open-source project from my research group at Cornell.
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by emin-gun-sirer 12y ago
This well-illustrated post is technically about the core Synod agreement protocol in Paxos. Building a consistent distributed service on top requires additional scaffolding and infrastructure. Typically, people layer on a system that implem
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by emin-gun-sirer 12y ago
It's critical to not conflate Bitcoin with ChangeTip. The two are, in effect, separate currencies. One is decentralized and backed by the blockchain, the other is centralized and backed by a company. A litmus test for centralized curre
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by emin-gun-sirer 12y ago
How does this product actually work, except by violating the standard TCP congestion avoidance algorithm?
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by emin-gun-sirer 12y ago
Co-author here. There is a common misconception that consensus of the Bitcoin community is correlated with the hashing power of the miners. A miner can have 51% of the hashing power, but if the blocks he produces are not accepted by clients
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by emin-gun-sirer 12y ago
To the contrary, we've been far more respectful and accommodating to the Bitcoin fringe than merited, and certainly far more than the other way around. After all, we took a fair amount of abuse for simply pointing out an objective weak
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by emin-gun-sirer 12y ago
The counterpoint from my colleague Ed Felten is based on a flawed understanding of how mining pools work and how pool participants are rewarded. Explained here: http://hackingdistributed.com/2013/11/08/fairwea
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by emin-gun-sirer 12y ago
Nice ad hominems you've got there. >In fact, the paper just formalized some concerns discussed in the mining community for years. This is false. Discussed here: http://hackingdistributed.com/2013/11/09&#x2F
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by emin-gun-sirer 12y ago
That's not the kind of restriction that stops pool mining. The trick is to enable the pool members to steal the blocks they discover. Andrew Miller, a grad student at UMD, has an ingenious scheme for doing this. I am pretty sure I put
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by emin-gun-sirer 13y ago
There are next-generation NoSQL data stores out there that are better than MongoDB on many axis (performance, consistency, fault-tolerance, API, backup speeds, etc). One of these (full disclosure: it's from my group) is HyperDex ( http
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by emin-gun-sirer 13y ago
Just curious: of the data that Zuckerberg could collect, what does he not collect? It should be pretty clear that this is not an endorsement of NSA's broad data collection activities. But credible leadership in this area requires tha
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by emin-gun-sirer 13y ago
No culture deserves to have its creation myths exposed or destroyed. Ironically, Newsweek's behavior makes a strong case for anonymous communication and payment systems.
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by emin-gun-sirer 13y ago
Author here. I think there is some subtlety around the technical point that may be getting lost. Ittay Eyal and I were the ones who discovered an attack against Bitcoin called selfish mining, where we showed how a miner could earn more than
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by emin-gun-sirer 13y ago
>The implications of my comment were not simply that gamma is reduced to zero, but that the whole problem is thrown out the window because the entire pool would be banned from the network (blacklisted). Ah, but even if detection worked p
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by emin-gun-sirer 13y ago
The math seems to be correct and borne out by simulations, even independent simulations devised by people who did not believe that the selfish mining attack would work [1]. So Stephen's point is that there may be operational procedures
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by emin-gun-sirer 13y ago
I'm one of the two authors of the selfish mining paper. Let me chime in on the selfish mining aspect of this generally insightful comment: > The interesting question remains: what happens when some pools start to implement this stra
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by emin-gun-sirer 13y ago
You mean "ACID transactions" and not SQL databases. Some NoSQL databases, such as HyperDex, provide ACID transactions.
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by emin-gun-sirer 13y ago
Let me use this opportunity to point out http://virtual-notary.org , an online witness to facts that can be checked online, where these facts are recorded in the Bitcoin blockchain. These go beyond the types of document proof of
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by emin-gun-sirer 13y ago
That blog post met with a lot of responses of the form "tl;dr but mongo was broken and it's fixed now, nothing to see here." Wasn't fixed then, doesn't seem to be fixed now [1]. And it's quite difficult to have
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by emin-gun-sirer 13y ago
I'm the author of the blog post, and just saw this resubmission on HN. Just wanted to quickly touch upon some of these points: * "It lies." Mongo lied at the time I wrote the post, and while the default has been changed, the
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by emin-gun-sirer 13y ago
The post assumes that Bitcoins will fail if they are not suitable as a store of value. It overlooks the fact that a currency can succeed as a medium of exchange, even if it is not suitable as a store of value.
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by emin-gun-sirer 13y ago
Timestamping services are not novel and date way back before 2012. The earliest work I know of is from AT&T back in the 80's, where they proposed to publish the hash in the NYT. The idea was so well established that there is even a

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