> > The proposed fix is to add a new rule on how > fees are handled. Some amount of every fee should be considered as burned > and can never be spent. I will propose 50% of the fee here, but there may > be better numbers that can be discovered prior to putting this into place. > If we'd like miners to continue to collect the same fees after this change, > we can suggest the default fee per transaction to be doubled I would propose another practical rule rather than burning 50% of the fee. For example, you can credit 50% of the transaction fee to the next block. Thus, the attacker cannot perform the attack with 0-fee any more, yet you don't have to double the price of the TX fee for the fix. Thanks, Loi Luu. On Tue, Jun 9, 2015 at 4:07 AM, Raystonn . wrote: > When implemented, the block size limit was put in place to prevent the > potential for a massive block to be used as an attack to benefit the miner > of that block. The theory goes that such a massive block would enrich its > miner by delaying other miners who are now busy downloading and validating > that huge block. The original miner of that large-block would be free to > continue hashing the next block, giving it an advantage. > > Unfortunately, this block size limit opened a different attack. Prior to > the limit, any attempt to spam the network by anyone other than someone > mining their own transactions would have been economically unfeasible. As > every transaction would have a fee, there would have been a real cost for > every minute of spam. The end result would have been a transfer of wealth > from spammer to Bitcoin miners, which would have harmed the spammers and > encouraged further mining of Bitcoin, a very antifragile outcome. > > But now we have the block size limit. Things are very different with this > feature in place. The beginning of a spam attack on the Bitcoin network > will incur transaction fees, just like before. But if spam continues at a > rate exceeding the block size limit long enough for transactions to be > dropped from mempools, the vast majority of spam transaction fees will > never > have to be paid. In fact, as real users gain in desperation and pay higher > fees to get their transactions through in a timely manner, the spammers > will > adjust their fees to minimize the cost of the attack and maximize > effectiveness. Using this method, they keep their fees at a point that > causes most of the spam transactions to be dropped without confirmation > (free spam), while forcing a floor for transaction fees. Thus, while spam > could be used by attackers to disable the network entirely, by paying > high-enough fees to actually fill the blocks with spam, it can also be used > by a single entity to force a transaction fee floor. Real users will be > forced to pay a transaction fee higher than the majority of the spam to get > their transactions confirmed. So this is an effective means for a minority > of miners to force higher fees through spam attacks, even in the face of > benevolent miners who would not support a higher fee floor by policy. > Miners would simply have no way to fix this, as they can only put in the > transactions that will fit under the block size limit. > > In the face of such a spam attack, Bitcoin's credibility and usability > would > be severely undermined. The block size limit enables this attack, and I > now > argue for its removal. But we can't just remove it and ignore the problem > that it was intended to address. We need a new fix for the large-block > problem described in the first paragraph that does not suffer from the > dropped-transaction spam-attack problem that is enabled by the block size > limit today. My proposal is likely to be controversial, and I'm very much > open to hearing other better proposals. > > Large blocks created by a miner as a means to spam other miners out of > competition is a problem because miners do not pay fees for their own > transactions when they mine them. They collect the fees they pay. This > breaks the economic barrier keeping people from spamming the network, as > the > spamming is essentially free. The proposed fix is to add a new rule on how > fees are handled. Some amount of every fee should be considered as burned > and can never be spent. I will propose 50% of the fee here, but there may > be better numbers that can be discovered prior to putting this into place. > If we'd like miners to continue to collect the same fees after this change, > we can suggest the default fee per transaction to be doubled. Half of > every > fee would be burned and disappear forever, effectively distributing the > value of those bitcoins across the entire money supply. The other half > would be collected by the miner of the block as is done today. This > solution would mean large blocks would cost a significant number of bitcoin > to create, even when all of the transactions are created by the miner of > that block. For this to work, we'd need to ensure a minimum fee is paid > for > most of the transactions in every block, and the new transaction fee rule > is > in place. Then the block size limit can be removed. > > Raystonn > > > > ------------------------------------------------------------------------------ > _______________________________________________ > Bitcoin-development mailing list > Bitcoin-development@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development >