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There's no way to know what the main chain is if you're only connected to attackers who are relaying blocks from a fork.

by aianus 13y ago

modeless 13y ago
Technically true, but the proof of work required to add blocks to a fork is the same as the real chain, so anyone wanting to send you fake blocks would need a significant fraction of the computing power of the whole network (in order to generate at least one fake block in a reasonable amount of time), in addition to controlling every node you speak with. Even if the attacker controlled 10% of the computing power of the network, they would only be able to generate approximately one block every hour and a half or so. After a few blocks that would start to look suspicious, since the average time between blocks is supposed to be 10 minutes.
- sktrdie 13y ago
  Right, but the point I was trying to make is that if you're only connected to attackers, they could broadcast only parts of the chain. Perhaps only the part they're interested in to bring out their attack. Bitcoin solves this by making the p2p connections as diverse as possible.
marcell 13y ago
Attackers can't control which nodes you connect to. The Satoshi client's node discover behavior is described here: https://en.bitcoin.it/wiki/Satoshi_Client_Node_Discovery https://en.bitcoin.it/wiki/Satoshi_Client_Node_Discovery. This blog post is pretty bad, and I suspect the author doesn't actually understand how bitcoin works. The part where the author says "the other 45 in the network know your real amount" implies some sort of voting mechanism, which is not how bitcoin works. This Youtube video is a much better explanation of the technical aspects of bitcoin: http://www.youtube.com/watch?v=Lx9zgZCMqXE http://www.youtube.com/watch?v=Lx9zgZCMqXE
- sktrdie 13y ago
  The client tries to be as diverse as possible when it comes to connecting to other nodes, but the state where you're only connected to attackers should not be avoid. That's what I was trying to explain in the post. > "the other 45 in the network know your real amount" implies some sort of voting mechanism, which is not how bitcoin works. Sorry I wasn't implying a voting mechanism. Simply that your account information is controlled by whomever has the majority of the computing power in the network.
maaku 13y ago
Yes, there is. Unless the attackers are maintaining comparable hash rates to the main network, you will notice the nethash drop.

There's no way to know what the main chain is if you're only connected to attackers who are relaying blocks from a fork.

by aianus 13y ago

There's no way to know what the main chain is if you're only connected to attackers who are relaying blocks from a fork.

modeless 13y ago

Technically true, but the proof of work required to add blocks to a fork is the same as the real chain, so anyone wanting to send you fake blocks would need a significant fraction of the computing power of the whole network (in order to generate at least one fake block in a reasonable amount of time), in addition to controlling every node you speak with. Even if the attacker controlled 10% of the computing power of the network, they would only be able to generate approximately one block every hour and a half or so. After a few blocks that would start to look suspicious, since the average time between blocks is supposed to be 10 minutes.

sktrdie 13y ago
Right, but the point I was trying to make is that if you're only connected to attackers, they could broadcast only parts of the chain. Perhaps only the part they're interested in to bring out their attack. Bitcoin solves this by making the p2p connections as diverse as possible.

marcell 13y ago

Attackers can't control which nodes you connect to. The Satoshi client's node discover behavior is described here: https://en.bitcoin.it/wiki/Satoshi_Client_Node_Discovery https://en.bitcoin.it/wiki/Satoshi_Client_Node_Discovery. This blog post is pretty bad, and I suspect the author doesn't actually understand how bitcoin works. The part where the author says "the other 45 in the network know your real amount" implies some sort of voting mechanism, which is not how bitcoin works. This Youtube video is a much better explanation of the technical aspects of bitcoin: http://www.youtube.com/watch?v=Lx9zgZCMqXE http://www.youtube.com/watch?v=Lx9zgZCMqXE

sktrdie 13y ago
The client tries to be as diverse as possible when it comes to connecting to other nodes, but the state where you're only connected to attackers should not be avoid. That's what I was trying to explain in the post. > "the other 45 in the network know your real amount" implies some sort of voting mechanism, which is not how bitcoin works. Sorry I wasn't implying a voting mechanism. Simply that your account information is controlled by whomever has the majority of the computing power in the network.

maaku 13y ago

Yes, there is. Unless the attackers are maintaining comparable hash rates to the main network, you will notice the nethash drop.