Emin Gün Sirer: Bitcoin is Still Broken

Emin Gün Sirer

Emin Gün Sirer is a computer science professor at Cornell University. His research spans operating systems, networking, and distributed systems. He’s also co-director of the Initiative for Cryptocurrencies & Contracts, which is an initiative of faculty members at Cornell University, Cornell Tech, UC Berkeley, UIUC and the Technion to help to advance the adoption of cryptocurrencies and smart contracts.
In 2002, he started Karma, an early cryptocurrency that was the first to utilize a proof-of-work concept. He has written several influential white papers and blog posts (on Hacking Distributed) that have altered the course of Ethereum’s development. He was among the first to warn about the vulnerabilities that led to the collapse of The DAO. He also acts as the Blockchain Advisor for the WeTrust project.
He is currently number 29 on the list of the Most Influential Blockchain People.

Most Influential Blockchain People

Terrance Jackson: In 2013, You and Ittay Eyal wrote “Bitcoin is Broken.” Is Bitcoin still broken?
Emin Gün Sirer: Indeed, we found the biggest known fundamental weakness in Satoshi Nakamoto’s consensus protocol, known as Selfish Mining. Using our strategy, one can subvert Satoshi’s protocol, and possibly make more money than their fair share, at the cost of disrupting the system’s behavior. Luckily, we provided a fix for selfish mining attacks for miners smaller than 25%, but the threat from large miners is always going to be present.
Now that the attack is well-known, the community knows how to detect such attacks and put pressure on the actors who launch them. In fact, if anything, the community is hyper-diligent against miners that are too big, and puts pressure on them to break them up. No Bitcoin miner is big enough to unilaterally go selfish and harm the system.
The situation is quite different in other cryptocurrencies, however. Selfish Mining could be employed against other smaller coins.

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