From cjp at ultimatestunts.nl Sun Aug 30 17:18:27 2015 From: cjp at ultimatestunts.nl (CJP) Date: Sun, 30 Aug 2015 19:18:27 +0200 Subject: [Lightning-dev] Loop attack with onion routing.. In-Reply-To: References: <874mjujyqe.fsf@rustcorp.com.au> <1440870652.4197.88.camel@hppg6.kloosterkade> Message-ID: <1440955107.5747.11.camel@hppg6.kloosterkade> > > I'm not sure the fine is necessarily small relative to the blockchain > fees, though (especially if the blockchain fee is zero...)? A long > chain might get fees into the 1% range, and for a moderate sized > payment ($5 coffee, 20 mBTC) that would be .2 mBTC, exceeding a 1kB > txn fee of .1 mBTC... You assume the present-day exchange rate. When scaling towards larger numbers of users and transactions, the exchange rate will increase a lot. This will make the blockchain tx fee much worse. With increasing numbers of users the route length in Lightning might also increase a bit (hence increase its tx fee too), but the situation is much better than with in-blockchain transactions. A very simplistic estimate of the exchange rate in a very ambitious scenario: assume a future world of 10e9 people, who have all reached developed-nation wealth, and who use Bitcoin for all their finances. Each of them can have 2.1 mBTC of savings. Assuming the average developed-nation person has about $10e3 savings in today's dollars, 2.1 mBTC savings in our scenario should be equivalent to $10e3 in today's dollars. So that is $4800 / mBTC = $4.8 mln / BTC! Note that the actual exchange rate in our hypothetical scenario will be much higher, since the dollar will have become worthless. CJP >