> There will always be a blocksize limit based on technological > considerations - the network has a finite bandwidth limit.
A bandwidth limit is not the same as a blocksize limit. Bandwidth is unique to every individual. Miners in China have different bandwidth and connectivity than miners in the U.S., for example. But the block size limit is dictated for eveyone. They are not comparable. > Without a blocksize limit the attacker would just flood the network until > the bandwidth usage became so great that consensus would fail, rendering > Bitcoin both worthless, and insecure. No, with no blocksize limit, a spammer would would flood the network with transactions until they ran out of money. Meanwhile, everyone would jump on board trying to mine the blocks to collect the fees from the spammers. It could be one of the greatest transfers of wealth ever. Bitcoin infrastructure would build up to handle the required bandwidth, paid for by the very entity spamming the network. Bitcoin would flourish, growing wildly as long as the fees kept coming. This is antifragility at its best. > The worst an attacker flooding the network with transactions with a > blocksize limit can do is raise costs, without harming security. No, at attacker flooding the network with transactions with a blocksize limit can keep their fees high enough that perhaps 1% of transactions coming from real end-users go through. At this point everyone would give up on Bitcoin as it would become completely unusable. The BTCUSD market would tank, making it even easier to pay the transaction fees to keep real transactions out of blocks, as it would continue to become cheaper and eventually cost-free to obtain the bitcoin fees through market purchase. -----Original Message----- From: Peter Todd Sent: Monday, June 08, 2015 2:44 PM To: Raystonn . Cc: Patrick Mccorry (PGR) ; Bitcoin Dev Subject: Re: [Bitcoin-development] New attack identified and potential solution described: Dropped-transaction spam attack against the blocksize limit On Mon, Jun 08, 2015 at 02:33:54PM -0700, Raystonn . wrote: > > the attack would be expensive. > > For attacks being waged to destroy Bitcoin by filling all blocks with spam > transactions, the attack succeeds when the attacker is well funded. This > gives well-funded private and/or public entities the means to destroy > Bitcoin if they desire. This is only true after the block size limit was > implemented. Without the block size limit, the spam doesn’t harm Bitcoin. > It simply enriches miners at the cost of the spammers, which is a nicely > antifragile quality. There will always be a blocksize limit based on technological considerations - the network has a finite bandwidth limit. Without a blocksize limit the attacker would just flood the network until the bandwidth usage became so great that consensus would fail, rendering Bitcoin both worthless, and insecure. The worst an attacker flooding the network with transactions with a blocksize limit can do is raise costs, without harming security. Keep in mind, that at some point it'd be cheaper to just 51% attack the network. Based on the current block subsidy of 25BTC/MB that's at the point where transaction fees are 25mBTC/KB, which corresponds to <$2/tx fees - not that cheap, but still quite affordable for a large percentage of Bitcoin's users right now. And that's the *absolute worst-case* attack possible. ------------------------------------------------------------------------------ _______________________________________________ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
