rich1.0npub1q5sgcakfxhw3ya93tvnpqeacvf32p6lw70hke53rkjnf9lhw9w8s43ps87https://nostr.ae/npub1q5sgcakfxhw3ya93tvnpqeacvf32p6lw70hke53rkjnf9lhw9w8s43ps87njumphttps://nostr.ae📅 Original date posted:2015-05-26 📝 Original message:What prevents RBF from being used for fraudulent payment reversals? Pay 1BTC to Alice for hard goods, then after you receive the goods broadcast a double spend of that transaction to pay Alice nothing? Your only cost is the higher network fee of the 2nd tx. Thanks, -Danny On Mon, May 25, 2015 at 5:10 PM, Peter Todd <pete at petertodd.org> wrote: > On Tue, May 26, 2015 at 12:03:09AM +0200, Mike Hearn wrote: > > CPFP also solves it just fine. > > CPFP is a significantly more expensive way of paying fees than RBF, > particularly for the use-case of defragmenting outputs, with cost > savings ranging from 30% to 90% > > > Case 1: CPFP vs. RBF for increasing the fee on a single tx > ---------------------------------------------------------- > > Creating an spending a P2PKH output uses 34 bytes of txout, and 148 > bytes of txin, 182 bytes total. > > Let's suppose I have a 1 BTC P2PKH output and I want to pay 0.1 BTC to > Alice. This results in a 1in/2out transaction t1 that's 226 bytes in size. > I forget to click on the "priority fee" option, so it goes out with the > minimum fee of 2.26uBTC. Whoops! I use CPFP to spend that output, > creating a new transaction t2 that's 192 bytes in size. I want to pay > 1mBTC/KB for a fast confirmation, so I'm now paying 418uBTC of > transaction fees. > > On the other hand, had I use RBF, my wallet would have simply > rebroadcast t1 with the change address decreased. The rules require you > to pay 2.26uBTC for the bandwidth consumed broadcasting it, plus the new > fee level, or 218uBTC of fees in total. > > Cost savings: 48% > > > Case 2: Paying multiple recipients in succession > ------------------------------------------------ > > Suppose that after I pay Alice, I also decide to pay Bob for his hard > work demonstrating cryptographic protocols. I need to create a new > transaction t2 spending t1's change address. Normally t2 would be > another 226 bytes in size, resulting in 226uBTC additional fees. > > With RBF on the other hand I can simply double-spend t1 with a > transaction paying both Alice and Bob. This new transaction is 260 bytes > in size. I have to pay 2.6uBTC additional fees to pay for the bandwidth > consumed broadcasting it, resulting in an additional 36uBTC of fees. > > Cost savings: 84% > > > Case 3: Paying multiple recipients from a 2-of-3 multisig wallet > ---------------------------------------------------------------- > > The above situation gets even worse with multisig. t1 in the multisig > case is 367 bytes; t2 another 367 bytes, costing an additional 367uBTC > in fees. With RBF we rewrite t1 with an additional output, resulting in > a 399 byte transaction, with just 36uBTC in additional fees. > > Cost savings: 90% > > > Case 4: Dust defragmentation > ---------------------------- > > My wallet has a two transaction outputs that it wants to combine into > one for the purpose of UTXO defragmentation. It broadcasts transaction > t1 with two inputs and one output, size 340 bytes, paying zero fees. > > Prior to the transaction confirming I find I need to spend those funds > for a priority transaction at the 1mBTC/KB fee level. This transaction, > t2a, has one input and two outputs, 226 bytes in size. However it needs > to pay fees for both transactions at once, resulting in a combined total > fee of 556uBTC. If this situation happens frequently, defragmenting > UTXOs is likely to cost more in additional fees than it saves. > > With RBF I'd simply doublespend t1 with a 2-in-2-out transaction 374 > bytes in size, paying 374uBTC. Even better, if one of the two inputs is > sufficiently large to cover my costs I can doublespend t1 with a > 1-in-2-out tx just 226 bytes in size, paying 226uBTC. > > Cost savings: 32% to 59%, or even infinite if defragmentation w/o RBF > costs you more than you save > > -- > 'peter'[:-1]@petertodd.org > 0000000000000000134ce6577d4122094479f548b997baf84367eaf0c190bc9f > > > ------------------------------------------------------------------------------ > One dashboard for servers and applications across Physical-Virtual-Cloud > Widest out-of-the-box monitoring support with 50+ applications > Performance metrics, stats and reports that give you Actionable Insights > Deep dive visibility with transaction tracing using APM Insight. > http://ad.doubleclick.net/ddm/clk/290420510;117567292;y > _______________________________________________ > Bitcoin-development mailing list > Bitcoin-development at lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20150526/4f1264c0/attachment.html>