Topic: DoS implications on long term success. (Read 856 times)

Peter's point is salient, which makes me think that what isn't protected from DoS is our meta-bitcoin systems, such as current iterations of CoinJoin, etc.

Maybe a meta-solution is pre-loaded small deposit to the CoinJoin server? The server can give the deposit back when requested, but DoS attempts result in a ban and "theft" of deposit.

(probably not possible in the case of the advanced CoinJoin setups where the server doesn't have much knowledge of what's going on, but just throwing something out there)

So, if I understand correctly, a DoS attack would have to be very well funded to get priority above any transaction that includes a moderate tx fee?

There seems to be an accelerating number of great developers getting involved with Bitcoin, either directly or via privately funded startups. It is my belief that with the core developers and the consistent influx of new interest, Bitcoin has a great chance of overcoming its growing pains. I have faith, and I wish I had the technical aptitude to truly understand the depths of the technology and contribute to its success in a more direct way.

Thank you for your thoughtful response and the work that you do for Bitcoin.

We've always known Bitcoin faces serious threats, e.g. scalability, mining centralization, blacklists, etc. Whether or not they're going to be solved is an open question, however it is clear there do exist potential solutions.

In the topic of Deanonymisation of clients in Bitcoin P2P network (https://bitcointalksearch.org/topic/new-paper-deanonymisation-of-clients-in-bitcoin-p2p-network-632124) Mike Hearn says:
My questions for the more technically apt amongst us are:
How big of an issue is DoS? Do you think it is solvable?

From what I have seen: (https://www.youtube.com/watch?v=2MtUKr05Y3I & https://www.youtube.com/watch?v=U-C3llqr_sEMike & the above post)
Mike Hearn seems rather unenthused about the success of Bitcoin recently. Does anybody know if this a view shared amongst other core developers?

Encrypting individual Bitcoin connections with overlay networks isn't as helpful as encrypting other kinds of connections, unless you're willing to waste large amounts of bandwidth and time. The problem is an observer who can watch traffic in and out of the encrypting server can watch a transaction-sized packet arrive over an encrypted connection and the decrypted transaction get relayed on to the P2P network a moment later. Given the highly predictable packet sizes and timings involved you can probably match them up very reliably. Delaying things doesn't really help - there aren't many transactions even across the whole Bitcoin network, so the anonymity set would be extremely small even if batched, and people want instantaneous response for things like in person transactions.

This could be solved by encrypting the entire P2P network (but then, it would be trivial for an adversary to connect to you and get the traffic unencrypted again), and by sending lots of cover traffic so it's harder to tell when a tx is being relayed. But that's very expensive, probably too expensive.

Privacy against privileged network observers is one thing. DoS is something else. As far as I know, nobody has ever built a P2P network that is really DoS resistant. It's not even clear it's possible with current technology. This may make Bitcoin technically unviable in the long run. However our current anti-DoS strategy is not that great and this is no news - e.g. banning an IP address because it sent an 81 byte message that cost almost nothing to process doesn't make a whole lot of sense (it would be better to put that IP at the bottom of a priority queue instead).