Hijacking Bitcoin: Large-scale Network Attacks on Cryptocurrencies

[The Young Turk]

Bitcoin is without a doubt the most successful cryptocurrency in circulation today, making it an extremely valuable target for attackers. Indeed, many studies have highlighted ways to compromise one or several Bitcoin nodes. In this paper, we take a different perspective and study the effect of large-scale network-level attacks such as the ones that may be launched by Autonomous Systems (ASes).
We show that attacks that are commonly believed to be hard, such as isolating 50% of the mining power, are actually within the reach of anyone with access to a BGP-enabled network and hijacking less than 900 prefixes. Once on path, AS-level adversaries can then partition the Bitcoin network or delay block propagation significantly. The key factors that enable these attacks are the extreme centralization of Bitcoin, both from a routing and a mining perspective, along with the fact that Bitcoin messages are sent unencrypted, without integrity guarantees.
We demonstrate the feasibility of large-scale attacks in practice against the deployed Bitcoin software and quantify their disruptive network-wide impact. The potential damage to Bitcoin is severe. By isolating a part of the network or delaying the propagation of blocks, network-level attackers can cause a significant amount of mining power to be wasted, leading to revenue losses and enabling a wide range of attacks such as double spending. We provide several suggestions on approaches to mitigate such attacks employing both short-term and long-term measures.

http://arxiv.org/abs/1605.07524
Direct link: http://arxiv.org/pdf/1605.07524v1.pdf

Any ideas & possible solutions about this problem?

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[Lauda]

We show that attacks that are commonly believed to be hard, such as isolating 50% of the mining power, are actually within the reach of anyone with access to a BGP-enabled network and hijacking less than 900 prefixes.

Of course a lot of people have access to the required equipment and have the required knowledge to try something like this. If it was easy to do, someone would have done it at least once already. However, the paper is rather interesting as it describes a lot different scenarios and proposes some solutions. I haven't found any relevant information beforehand, but to address this point:

7.2 Longer-term measures
Encrypt Bitcoin Communication

BIP 151 is supposed to encrypt the peer-to-peer traffic to make individual analysis harder.
I'll see if I can get some direct feedback for that paper.

[Kprawn]

How many years is this now, and nobody has successfully brought down the whole network? There are simply too many nodes out there and many of these nodes are behind good firewalls. An attack

like this will only have a short term influence, because new nodes can be up and running within hours. I do not see this as a serious risk, but people should prepare for attacks like this, and it's a good

strategy to be ready.... just in case, they are successful. 

[sbtctalk]

Are there any incentives in running a relay node yet?

There should have an incentive system to encourage more nodes.