Big blocks and Tor

I think I first heard this objection to a larger maximum block size from Peter Todd, Chief Scientist of ViaCoin:

More transactions makes it more difficult to keep Bitcoin activity private from oppressive governments.

That is hard to argue with– obviously the more you do something, the more likely you will get noticed. But engineering is about tradeoffs, so how much more likely is somebody to get noticed by their oppressive government if they are using a Bitcoin system that supports sixty, rather than three, transactions per second?

Well, if they are just transacting with Bitcoin using a lightweight wallet, there is no difference. Lightweight wallets (meaning any wallet except for Bitcoin Core or Armory) only download transactions relevant to them. They are unaffected by changes to the maximum block size.

But what if you want to be a miner in some oppressive country?

Well, if you have good connectivity to a mining pool outside the country you should be able to connect to it over Tor. And, again, you will be unaffected by changes to the maximum block size, because you just need 80-byte block headers.

But what if you are in an oppressive country and you want to participate in the network as a full node, or want to solo mine, or want to use “getblocktemplate” when mining so you have complete control over what transactions you mine?

Well, in that case the simplest solution is to pay $10 per month to a hosting provider in a country that is NOT oppressive. Run a full node there, and if you have mining equipment in your house, connect to it over an encrypted connection (an ssh tunnel would work nicely). Again, bandwidth from your oppressive internet service provider will be the same no matter how busy the Bitcoin network gets.

But what if you don’t have $10 per month to spend?

My advice would be to stick with running a lightweight wallet running over Tor, or connecting to a mining pool via Tor.

You could run a full node over Tor, but even with one megabyte blocks that would be over 100 megabytes of encrypted Tor traffic every day. The risk of jack-booted thugs breaking down your door and demanding to know what you are doing far outweigh the benefits of running a fully validating node.