Hijacking Bitcoin: Routing Attacks on Cryptocurrencies

https://btc-hijack.ethz.ch/

by federicoponzi • 9 years ago

141 45 9 years ago

btc-hijack.ethz.ch

wonderous• 9 years ago

> “Moreover, most of the traffic exchanged between Bitcoin nodes traverse few ISPs. Indeed, our results indicate that 60% of all possible Bitcoin connections cross 3 ISPs. In other words, 3 ISPs can see 60% of all Bitcoin traffic.”

Direct link to the paper:

https://btc-hijack.ethz.ch/files/btc_hijack.pdf

albeebe1• 9 years ago

Level 3, Google, Facebook

kanzure2• 9 years ago

One of the authors gave a talk earlier this month at Stanford on lightning network and fees, http://diyhpl.us/wiki/transcripts/scalingbitcoin/stanford-20...

Buttes• 9 years ago

This talk is borderline unreadable. Are there slides or something I'm missing?

kanzure2• 9 years ago

https://www.youtube.com/watch?v=3pd6xHjLbhs&t=1h3m

idibidiart6• 9 years ago

Also like I said removal of net neutrality regulations means ISPs esp big ones can kill Bitcoin by blocking the default port used by the Bitcoin client and ISPs can more than just blocking a certain port. ISPs can identify and block all P2P traffic (anything that is not being sent or received to/from an approved central service) and do it in the name of protecting MPAA member revenue or whatever blanket execuse like killing off encrypted p2p communication like Signal et al)

EGreg3• 9 years ago

To be fair, can't backbone providers already do this?

https://www.wired.com/2014/06/net_neutrality_missing/

idibidiart6• 9 years ago

I meant legally they can't. They'd be sued and defeated in court. But not if Net Neutrality rules are undone.

wmf• 9 years ago

Is there any evidence that ISPs want to do this?

(Hint: ISP didn't block BitTorrent because of the MPAA.)

TehCorwiz2• 9 years ago

No, but I'm sure that given the right financial incentives (hint: third-party) they'd be open to implementing this in practice.

pas3• 9 years ago

Comcast blocked BitTorrent in 2008.

https://www.theverge.com/2017/11/22/16691794/net-neutrality-...

bufferoverflow• 9 years ago

That would not kill Bitcoin. Nodes will quickly switch to different port, maybe even 80.

idibidiart6• 9 years ago

Here to all the folks who are A) not legal scholars but pretending to be from their mom's basement and B) unable to reason about the implications but still assert their opinions, there are a ton of references to this issue. Here is one:

https://www.coindesk.com/eroding-net-neutrality-hurt-bitcoin...

tlrobinson• 9 years ago

If you’re concerned about this type of attack it’s pretty easy to defend against. All it takes to avoid partition is a single connection across a VPN, Tor, or even satellite (https://blockstream.com/satellite/).

nikcub• 9 years ago

BIP150[0] adds peer authentication, BIP151 adds encrypted peer communication. Having them implemented and enforced is probably overdue - afaik so far i've only seen bcoin[2] implement it

[0] https://github.com/bitcoin/bips/blob/master/bip-0150.mediawi...

[1] https://github.com/bitcoin/bips/blob/master/bip-0151.mediawi...

[2] https://github.com/bcoin-org/bcoin

Laforet4• 9 years ago

None of the bitcoin core developers have much experience in network engineering nor do they recognise the importance of having robust netcode. It is no susprise that they see no urgency to address the vulns.

Morever, their obsession with phasing in every change via a soft fork (i.e. updated nodes must be eternally backwards compatible with older versions) puts an unreasonable constraint on protocol development and snuffs any progress that is ever so slightly controversial.

mitchellberry2• 9 years ago

None of the bitcoin core developers have much experience in network engineering

https://github.com/bitcoin/bitcoin/graphs/contributors

Many are anonymous or use psuedonoyms. Cohort easily over 100.

Seems like an incredibly bold assertion to make about such a large group of developers.

VMG• 9 years ago

Morever, their obsession with phasing in every change via a soft fork (i.e. updated nodes must be eternally backwards compatible with older versions)

This "obsession" is about the consensus layer, for very good reasons.

The peer-to-peer protocol is much more flexible, and a lot of work is being done there.

KasianFranks• 9 years ago

Crypto is misunderstood but can't be ignored. Welcome to the disruption and destruction of the VC model for founders that move things forward.

albertgoeswoof2• 9 years ago

"An attacker can use routing attacks to partition the network into two (or more) disjoint components. By preventing nodes within a component to communicate with nodes outside of it, the attacker forces the creation of parallel blockchains. After the attack stops, all blocks mined within the smaller component will be discarded together with all included transactions and the miners revenue. "

How does bitcoin protect against this from happening by accident? Could someone surround my node with malicious nodes and put me on a forked chain?

runeks• 9 years ago

Could someone surround my node with malicious nodes and put me on a forked chain?

Yes. You can’t know about blocks you don’t hear about. However:

1. Unless they can match the hashing power of the rest of the network, they can only publish new blocks to you at a very low rate (e.g. every 100 minutes if they have 10% of the hashing power)

2. If you connect to just a single node which tells the truth, you will discard the forked chain (again, unless the attackers can match the hash rate of the rest of the network)

All in all, proof-of-work makes it pretty easy for you to notice that something weird is happening.

How does bitcoin protect against this from happening by accident?

You can prevent nodes from connecting to you (no inbound connections), such that you choose (randomly) which nodes to connect to. Choose a sufficiently high node count, and you’re almost certain that you don’t select a group of coordinating malicious nodes.

Side note: It would also be interesting to analyze the impact of this attack in the context of a proof-of-stake blockchain. I assume, although I’m not certain, that the attacked node would just consider the current stakers as defunct if the attackers don’t deliver blocks from them, and that the attackers would be able to become the new stakers, since the attackers would be able to censor competing staking transactions.

ben_w• 9 years ago

You can prevent nodes from connecting to you (no inbound connections), such that you choose (randomly) which nodes to connect to. Choose a sufficiently high node count, and you’re almost certain that you don’t select a group of coordinating malicious nodes.

This sounds suspiciously like either a) choosing who to trust in advance, which negates one of the few benefits of blockchain-based cryptocurrencies that I accept exist (even if I don’t value it highly); or b) relying on random numbers being both fair and not being tampered with, even though over-reliance on that is one of the common failure modes with cryptography in general.

Hijacking Bitcoin: Routing Attacks on Cryptocurrencies

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