Viewing profile — emin-gun-sirer

>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 possib…

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…

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 …

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.…

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 e…

The popular NTP server time.nist.gov is having DNS problems, at least from our vantage point on the US east coast. For us, this has meant that regularly scheduled security reports …

HyperDex provides scalable and high-performance transactions. While it is strongly (not eventually) consistent, the underlying technique we use to achieve atomicity of transactions…

>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 to…

Yes, it's an open-source project from my research group at Cornell.

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 inf…

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 b…

How does this product actually work, except by violating the standard TCP congestion avoidance algorithm?

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 powe…

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 am…

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://hackingdistr…

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://hackingdistr…

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 i…

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 (…

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 activiti…

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.

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 self…

>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 …

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 Step…

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 …