3 ms·
The point of proof-of-work is that the attack you describe, "transmitting a modified blockchain", is very, very expensive. Essentially any plausible block is "s
by gojomo 12y ago
The point of proof-of-work is that the attack you describe, "transmitting a modified blockchain", is very, very expensive. Essentially any plausible block is "signed & trusted" by the very-difficult partial-hash-collision embedded within.
- teraflop 12y agoIn this situation, not really. Bitcoin's proof-of-work scheme means that if you see two different versions of the blockchain, whichever chain is longer will (with very high probability) be the globally-accepted version. But that assumes you have the ability to communicate with at least one non-malicious node. In this case, there's a single communications channel that could be spoofed by anyone with a transmitter powerful enough to drown out the legitimate signal.
- servowire 12y agoNo, because proof-of-work prevents you from "faking" a blockchain. Let's say we are at block 100 and you would want to fake "the blockchain". You would have to fake a block every 10 minutes, but that requires mining, because you can't just make a block - it has to fit the previous one with the right difficulty. You could stop sending new blocks, but that would alarm the endpoint because it will be stuck at block 100 (in our example). The Proof-of-work scheme is pretty innovative.
- mike_hearn 12y agoIt means if you could override the signal with your own AND had a lot of hash power, you could slowly drag down the difficulty of your fake chain and eventually it'd be easy to create. But indeed you must (assuming the device managed to see the real block chain at least once) do a lot of computational work to start with.