[Bitcoin-development] Atomic coin swapping?
Forum URL: https://bitcointalk.org/index.php?topic=112007.0 gmaxwell was talking about colored coins[1] in IRC recently. They are potentially interesting in the context of distributed bonds[2], which I am currently pursuing with pybond[3]. Here is the problem I am trying to solve, does the crowd have an answer? 1. Alice transfers a 1-satoshi colored coin to Bob. 2. Bob transfers 100 BTC to Alice. May be restricted to 1 txout, if that eases implementation details. 3. Steps #1 and #2 happen as an atomic unit, all-or-none. 4. Alice and Bob must both approve this atomic transfer of coins, with appropriate signatures. Is this possible within the current bitcoin system? As far as I can see, the answer is no but maybe I'm missing something. My best guess to the answer is possible, but requires a new SIGHASH_* type? [1] https://bitcointalk.org/index.php?topic=106449.0 [2] https://bitcointalk.org/index.php?topic=92421.0 [3] https://github.com/jgarzik/pybond -- Jeff Garzik exMULTI, Inc. jgar...@exmulti.com -- How fast is your code? 3 out of 4 devs don\\\'t know how their code performs in production. Find out how slow your code is with AppDynamics Lite. http://ad.doubleclick.net/clk;262219672;13503038;z? http://info.appdynamics.com/FreeJavaPerformanceDownload.html ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Atomic coin swapping?
I'm very interested in this. I was expecting transitive/multi-hop transactions (Ripple) with colored coins, and I don't understand why is not possible. From https://en.bitcoin.it/wiki/Contracts --- SIGHASH_ALL: This is the default. It indicates that everything about the transaction is signed, except for the input scripts. Signing the input scripts as well would obviously make it impossible to construct a transaction, so they are always blanked out. Note, though, that other properties of the input, like the connected output and sequence numbers, are signed; it's only the scripts that are not. Intuitively, it means I agree to put my money in, if everyone puts their money in and the outputs are this. --- Why Signing the input scripts as well would obviously make it impossible to construct a transaction? I don't understand that part. I think a new SIGHASH_* type that doesn't pay attention to that obviously is needed to achieve what we want. Say we want the following transaction: A 1 satoshi - B 1 satoshi - C 100 btc - A It would be necessary to sign the following: Inputs: from srcA, from srcB, Outputs: 1 satoshi to destB, 1 satoshi to destC, 100 btc to destA from srcC is not really necessary. This same scheme can be used for n-hops. What am I missing? On 9/22/12, Jeff Garzik jgar...@exmulti.com wrote: Forum URL: https://bitcointalk.org/index.php?topic=112007.0 gmaxwell was talking about colored coins[1] in IRC recently. They are potentially interesting in the context of distributed bonds[2], which I am currently pursuing with pybond[3]. Here is the problem I am trying to solve, does the crowd have an answer? 1. Alice transfers a 1-satoshi colored coin to Bob. 2. Bob transfers 100 BTC to Alice. May be restricted to 1 txout, if that eases implementation details. 3. Steps #1 and #2 happen as an atomic unit, all-or-none. 4. Alice and Bob must both approve this atomic transfer of coins, with appropriate signatures. Is this possible within the current bitcoin system? As far as I can see, the answer is no but maybe I'm missing something. My best guess to the answer is possible, but requires a new SIGHASH_* type? [1] https://bitcointalk.org/index.php?topic=106449.0 [2] https://bitcointalk.org/index.php?topic=92421.0 [3] https://github.com/jgarzik/pybond -- Jeff Garzik exMULTI, Inc. jgar...@exmulti.com -- How fast is your code? 3 out of 4 devs don\\\'t know how their code performs in production. Find out how slow your code is with AppDynamics Lite. http://ad.doubleclick.net/clk;262219672;13503038;z? http://info.appdynamics.com/FreeJavaPerformanceDownload.html ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development -- Jorge Timón -- How fast is your code? 3 out of 4 devs don\\\'t know how their code performs in production. Find out how slow your code is with AppDynamics Lite. http://ad.doubleclick.net/clk;262219672;13503038;z? http://info.appdynamics.com/FreeJavaPerformanceDownload.html ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Atomic coin swapping?
Why Signing the input scripts as well would obviously make it impossible to construct a transaction? As it states in the source code, signatures cannot sign themselves. If scriptSigs were included in the data that is being signed, the act of inserting the newly calculated signature for one input would break the signatures for all the others. -- How fast is your code? 3 out of 4 devs don\\\'t know how their code performs in production. Find out how slow your code is with AppDynamics Lite. http://ad.doubleclick.net/clk;262219672;13503038;z? http://info.appdynamics.com/FreeJavaPerformanceDownload.html___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Atomic coin swapping?
On Sat, Sep 22, 2012 at 5:10 AM, Jorge Timón timon.elvi...@gmail.com wrote: I'm very interested in this. I was expecting transitive/multi-hop transactions (Ripple) with colored coins, and I don't understand why is not possible. From https://en.bitcoin.it/wiki/Contracts --- SIGHASH_ALL: This is the default. It indicates that everything about Yes, SIGHASH_ALL was the crucial piece I was missing. I have updated the post to add a concrete example with as much detail as necessary for programmers to recreate. Review requested: https://bitcointalk.org/index.php?topic=112007.msg1212356#msg1212356 -- Jeff Garzik exMULTI, Inc. jgar...@exmulti.com -- How fast is your code? 3 out of 4 devs don\\\'t know how their code performs in production. Find out how slow your code is with AppDynamics Lite. http://ad.doubleclick.net/clk;262219672;13503038;z? http://info.appdynamics.com/FreeJavaPerformanceDownload.html ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
