* [bitcoin-dev] OP_CHECKWILDCARDSIGVERIFY or "Wildcard Inputs" or "Coalescing Transactions" @ 2015-11-24 17:34 Chris Priest 2015-11-24 20:32 ` Gavin Andresen 2015-11-24 21:51 ` Bryan Bishop 0 siblings, 2 replies; 11+ messages in thread From: Chris Priest @ 2015-11-24 17:34 UTC (permalink / raw) To: bitcoin-dev Here is the problem I'm trying to solve with this idea: Lets say you create an address, publish the address on your blog, and tell all your readers to donate $0.05 to that address if they like your blog. Lets assume you receive 10,000 donations this way. This all adds up to $500. The problem is that because of the way the bitcoin payment protocol works, a large chunk of that money will go to fees. If one person sent you a single donation of $500, you would be able to spend most of the $500, but since you got this coin by many smaller UTXO's, your wallet has to use a higher tx fee when spending this coin. The technical reason for this is that you have to explicitly list each UTXO individually when making bitcoin transactions. There is no way to say "all the utxos". This post describes a way to achieve this. I'm not yet a bitcoin master, so there are parts of this proposal that I have not yet figured out entirely, but I'm sure other people who know more could help out. **OP_CHECKWILDCARDSIGVERIFY** First, I propose a new opcode. This opcode works exactly the same as OP_CHECKSIGVERIFY, except it only evaluates true if the signature is a "wildcard signature". What is a wildcard signature you ask? This is the part that I have not yet 100% figured out yet. It is basically a signature that was created in such a way that expresses the private key owners intent to make this input a *wildcard input* ** wildcard inputs ** A wildcard input is defined as a input to a transaction that has been signed with OP_CHECKWILDCARDSIGVERIFY. The difference between a wildcard input and a regular input is that the regular input respects the "value" or "amount" field, while the wildcard input ignores that value, and instead uses the value of *all inputs* with a matching locking script. ** coalescing transaction" A bitcoin transaction that ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [bitcoin-dev] OP_CHECKWILDCARDSIGVERIFY or "Wildcard Inputs" or "Coalescing Transactions" 2015-11-24 17:34 [bitcoin-dev] OP_CHECKWILDCARDSIGVERIFY or "Wildcard Inputs" or "Coalescing Transactions" Chris Priest @ 2015-11-24 20:32 ` Gavin Andresen 2015-11-24 21:01 ` Chris Priest 2015-11-24 21:51 ` Bryan Bishop 1 sibling, 1 reply; 11+ messages in thread From: Gavin Andresen @ 2015-11-24 20:32 UTC (permalink / raw) To: Chris Priest; +Cc: Bitcoin Dev [-- Attachment #1: Type: text/plain, Size: 1863 bytes --] On Tue, Nov 24, 2015 at 12:34 PM, Chris Priest via bitcoin-dev < bitcoin-dev@lists•linuxfoundation.org> wrote: > The technical reason for this is that you have to explicitly list each > UTXO individually when making bitcoin transactions. There is no way to > say "all the utxos". This post describes a way to achieve this. I'm > not yet a bitcoin master, so there are parts of this proposal that I > have not yet figured out entirely, but I'm sure other people who know > more could help out. > So every input has: 32-byte hash (transaction being spent) 4-byte output (output being spent) 4-byte sequence number ... plus the scriptSig. Which is as small as about 73 bytes if you're spending a raw OP_CHECKSIG (which you can't do as a bitcoin address, but could via the BIP70 payment protocol), and which is at least two serialized bytes. Best case for any scheme to coalesce scriptSigs would to somehow make all-but-the-first scriptSig zero-length, so the inputs would be 42 bytes instead of 40+73 bytes -- the coalesce transaction would be about one-third the size, so instead of paying (say) $1 in transaction fees you'd pay 37 cents. That's in the gray are of the "worth doing" threshold-- if it was a 10x improvement (pay 10 cents instead of $1) it'd be in my personal "definitely worth the trouble of doing" category. RE: the scheme: an OP_RINGSIGVERIFY is probably the right way to do this: https://en.wikipedia.org/wiki/Ring_signature The funding transactions would be: <public key> OP_RINGSIGVERIFY ... which might could be redeemed with <ring signature> for one input and then... uhh... maybe just <index_to_input_with_signature> for the other inputs that are part of the same ring signature group (OP_0 if the first input has the signature that is good for all the other public keys, which would be the common case). -- -- Gavin Andresen [-- Attachment #2: Type: text/html, Size: 2726 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [bitcoin-dev] OP_CHECKWILDCARDSIGVERIFY or "Wildcard Inputs" or "Coalescing Transactions" 2015-11-24 20:32 ` Gavin Andresen @ 2015-11-24 21:01 ` Chris Priest 0 siblings, 0 replies; 11+ messages in thread From: Chris Priest @ 2015-11-24 21:01 UTC (permalink / raw) To: Gavin Andresen; +Cc: Bitcoin Dev A coalescing transaction in my scheme is the same size as a normal transaction. You only include one UTXO, the rest are implied based on the presence of the OP_CHECKWILDCARDSIGVERIFY opcode. The code that determines if a UTXO is spent or not will need to be modified to include a check to see if any matching coalescing transactions exist in any later block. Maybe there should be a "coalescing pool" containing all coalescing transactions that make such a check faster. The part I'm not too sure about is the "wildcard signature". I'm not too versed in cryptography to know how exactly to pull this off, but I think it should be simple. You'd just have to some way inject a flag into the signing process that can be verified later. I originally wanted the "wildcardness" of the transaction expressed by the transaction version number. Basically any input that exists within a "version 2 transaction" is viewed as a wildcard input. Then I realized whats to stop someone from modifying the transaction from version 1 to version 2 and stealing someones funds. The "wildcardness" must be expressed in the signature so you know that the private key holder intended all inputs to be included. Hence the need for a new opcode. btw, this scheme is definitely in the 10x or higher gain. You could potentially spend an unlimited number of UTXOs this way. On 11/24/15, Gavin Andresen <gavinandresen@gmail•com> wrote: > On Tue, Nov 24, 2015 at 12:34 PM, Chris Priest via bitcoin-dev < > bitcoin-dev@lists•linuxfoundation.org> wrote: > >> The technical reason for this is that you have to explicitly list each >> UTXO individually when making bitcoin transactions. There is no way to >> say "all the utxos". This post describes a way to achieve this. I'm >> not yet a bitcoin master, so there are parts of this proposal that I >> have not yet figured out entirely, but I'm sure other people who know >> more could help out. >> > > So every input has: > 32-byte hash (transaction being spent) > 4-byte output (output being spent) > 4-byte sequence number > ... plus the scriptSig. Which is as small as about 73 bytes if you're > spending a raw OP_CHECKSIG (which you can't do as a bitcoin address, but > could via the BIP70 payment protocol), and which is at least two serialized > bytes. > > Best case for any scheme to coalesce scriptSigs would to somehow make > all-but-the-first scriptSig zero-length, so the inputs would be 42 bytes > instead of 40+73 bytes -- the coalesce transaction would be about one-third > the size, so instead of paying (say) $1 in transaction fees you'd pay 37 > cents. > > That's in the gray are of the "worth doing" threshold-- if it was a 10x > improvement (pay 10 cents instead of $1) it'd be in my personal "definitely > worth the trouble of doing" category. > > RE: the scheme: an OP_RINGSIGVERIFY is probably the right way to do this: > https://en.wikipedia.org/wiki/Ring_signature > > The funding transactions would be: <public key> OP_RINGSIGVERIFY > ... which might could be redeemed with <ring signature> for one input and > then... uhh... maybe just <index_to_input_with_signature> for the other > inputs that are part of the same ring signature group (OP_0 if the first > input has the signature that is good for all the other public keys, which > would be the common case). > > -- > -- > Gavin Andresen > ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [bitcoin-dev] OP_CHECKWILDCARDSIGVERIFY or "Wildcard Inputs" or "Coalescing Transactions" 2015-11-24 17:34 [bitcoin-dev] OP_CHECKWILDCARDSIGVERIFY or "Wildcard Inputs" or "Coalescing Transactions" Chris Priest 2015-11-24 20:32 ` Gavin Andresen @ 2015-11-24 21:51 ` Bryan Bishop 2015-11-24 23:28 ` Dave Scotese 1 sibling, 1 reply; 11+ messages in thread From: Bryan Bishop @ 2015-11-24 21:51 UTC (permalink / raw) To: Chris Priest, Bryan Bishop; +Cc: Bitcoin Dev [-- Attachment #1: Type: text/plain, Size: 370 bytes --] On Tue, Nov 24, 2015 at 11:34 AM, Chris Priest via bitcoin-dev < bitcoin-dev@lists•linuxfoundation.org> wrote: > **OP_CHECKWILDCARDSIGVERIFY** Some (minor) discussion of this idea in -wizards earlier today starting near near "09:50" (apologies for having no anchor links): http://gnusha.org/bitcoin-wizards/2015-11-24.log - Bryan http://heybryan.org/ 1 512 203 0507 [-- Attachment #2: Type: text/html, Size: 921 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [bitcoin-dev] OP_CHECKWILDCARDSIGVERIFY or "Wildcard Inputs" or "Coalescing Transactions" 2015-11-24 21:51 ` Bryan Bishop @ 2015-11-24 23:28 ` Dave Scotese 2015-11-24 23:48 ` Chris Priest 0 siblings, 1 reply; 11+ messages in thread From: Dave Scotese @ 2015-11-24 23:28 UTC (permalink / raw) To: Bitcoin Dev [-- Attachment #1: Type: text/plain, Size: 1946 bytes --] What is required to spend bitcoin is that input be provided to the UTXO script that causes it to return true. What Chris is proposing breaks the programmatic nature of the requirement, replacing it with a requirement that the secret be known. Granted, the secret is the only requirement in most cases, but there is no built-in assumption that the script always requires only that secret. This idea could be applied by having the wildcard signature apply to all UTXOs that are of a standard form and paid to a particular address, and be a signature of some kind of message to that effect. I imagine the cost of re-scanning the UTXO set to find them all would justify a special extra mining fee for any transaction that used this opcode. Please be blunt about any of my own misunderstandings that this email makes clear. On Tue, Nov 24, 2015 at 1:51 PM, Bryan Bishop via bitcoin-dev < bitcoin-dev@lists•linuxfoundation.org> wrote: > On Tue, Nov 24, 2015 at 11:34 AM, Chris Priest via bitcoin-dev < > bitcoin-dev@lists•linuxfoundation.org> wrote: > >> **OP_CHECKWILDCARDSIGVERIFY** > > > Some (minor) discussion of this idea in -wizards earlier today starting > near near "09:50" (apologies for having no anchor links): > http://gnusha.org/bitcoin-wizards/2015-11-24.log > > - Bryan > http://heybryan.org/ > 1 512 203 0507 > > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists•linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > > -- I like to provide some work at no charge to prove my value. Do you need a techie? I own Litmocracy <http://www.litmocracy.com> and Meme Racing <http://www.memeracing.net> (in alpha). I'm the webmaster for The Voluntaryist <http://www.voluntaryist.com> which now accepts Bitcoin. I also code for The Dollar Vigilante <http://dollarvigilante.com/>. "He ought to find it more profitable to play by the rules" - Satoshi Nakamoto [-- Attachment #2: Type: text/html, Size: 3299 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [bitcoin-dev] OP_CHECKWILDCARDSIGVERIFY or "Wildcard Inputs" or "Coalescing Transactions" 2015-11-24 23:28 ` Dave Scotese @ 2015-11-24 23:48 ` Chris Priest 2015-11-25 0:38 ` Jannes Faber 0 siblings, 1 reply; 11+ messages in thread From: Chris Priest @ 2015-11-24 23:48 UTC (permalink / raw) To: Dave Scotese; +Cc: Bitcoin Dev > This idea could be applied by having the wildcard signature apply to all > UTXOs that are of a standard form and paid to a particular address, and be > a signature of some kind of message to that effect. I think this is true. Not *all* transactions will be able to match the wildcard. For instance if someone sent some crazy smart contract tx to your address, the script associated with that tx will be such that it will not apply to the wildcard. Most "vanilla" utxos that I've seen have the formula: OP_DUP OP_HASH160 [a hash corresponding to your address] OP_EQUALVERIFY OP_CHECKSIG". Just UTXOs in that form could apply to the wildcard. On 11/24/15, Dave Scotese via bitcoin-dev <bitcoin-dev@lists•linuxfoundation.org> wrote: > What is required to spend bitcoin is that input be provided to the UTXO > script that causes it to return true. What Chris is proposing breaks the > programmatic nature of the requirement, replacing it with a requirement > that the secret be known. Granted, the secret is the only requirement in > most cases, but there is no built-in assumption that the script always > requires only that secret. > > This idea could be applied by having the wildcard signature apply to all > UTXOs that are of a standard form and paid to a particular address, and be > a signature of some kind of message to that effect. I imagine the cost of > re-scanning the UTXO set to find them all would justify a special extra > mining fee for any transaction that used this opcode. > > Please be blunt about any of my own misunderstandings that this email makes > clear. > > On Tue, Nov 24, 2015 at 1:51 PM, Bryan Bishop via bitcoin-dev < > bitcoin-dev@lists•linuxfoundation.org> wrote: > >> On Tue, Nov 24, 2015 at 11:34 AM, Chris Priest via bitcoin-dev < >> bitcoin-dev@lists•linuxfoundation.org> wrote: >> >>> **OP_CHECKWILDCARDSIGVERIFY** >> >> >> Some (minor) discussion of this idea in -wizards earlier today starting >> near near "09:50" (apologies for having no anchor links): >> http://gnusha.org/bitcoin-wizards/2015-11-24.log >> >> - Bryan >> http://heybryan.org/ >> 1 512 203 0507 >> >> _______________________________________________ >> bitcoin-dev mailing list >> bitcoin-dev@lists•linuxfoundation.org >> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev >> >> > > > -- > I like to provide some work at no charge to prove my value. Do you need a > techie? > I own Litmocracy <http://www.litmocracy.com> and Meme Racing > <http://www.memeracing.net> (in alpha). > I'm the webmaster for The Voluntaryist <http://www.voluntaryist.com> which > now accepts Bitcoin. > I also code for The Dollar Vigilante <http://dollarvigilante.com/>. > "He ought to find it more profitable to play by the rules" - Satoshi > Nakamoto > ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [bitcoin-dev] OP_CHECKWILDCARDSIGVERIFY or "Wildcard Inputs" or "Coalescing Transactions" 2015-11-24 23:48 ` Chris Priest @ 2015-11-25 0:38 ` Jannes Faber 2015-11-25 1:26 ` Chris Priest 0 siblings, 1 reply; 11+ messages in thread From: Jannes Faber @ 2015-11-25 0:38 UTC (permalink / raw) To: Bitcoin Dev [-- Attachment #1: Type: text/plain, Size: 3950 bytes --] Few issues I can think of: 1. In its basic form this encourages address reuse. Unless the wildcard can be constructed such that it can match a whole branch of an HD wallet. Although I guess that would tie all those addresses together making HD moot to begin with. 2. Sounds pretty dangerous during reorgs. Maybe such a transaction should include a block height which indicates the maximum block that any utxo can match. With the requirement that the specified block height is at least 100 blocks in the past. Maybe add a minimum block height as well to prevent unnecessary scanning (with the requirement that at least one utxo must be in that minimum block). 3. Seems like a nice way to the reduce utxo set. But hard to say how effective it would really be. On 25 Nov 2015 12:48 a.m., "Chris Priest via bitcoin-dev" < bitcoin-dev@lists•linuxfoundation.org> wrote: > > This idea could be applied by having the wildcard signature apply to all > > UTXOs that are of a standard form and paid to a particular address, and > be > > a signature of some kind of message to that effect. > > I think this is true. Not *all* transactions will be able to match the > wildcard. For instance if someone sent some crazy smart contract tx to > your address, the script associated with that tx will be such that it > will not apply to the wildcard. Most "vanilla" utxos that I've seen > have the formula: OP_DUP OP_HASH160 [a hash corresponding to your > address] OP_EQUALVERIFY OP_CHECKSIG". Just UTXOs in that form could > apply to the wildcard. > > On 11/24/15, Dave Scotese via bitcoin-dev > <bitcoin-dev@lists•linuxfoundation.org> wrote: > > What is required to spend bitcoin is that input be provided to the UTXO > > script that causes it to return true. What Chris is proposing breaks the > > programmatic nature of the requirement, replacing it with a requirement > > that the secret be known. Granted, the secret is the only requirement in > > most cases, but there is no built-in assumption that the script always > > requires only that secret. > > > > This idea could be applied by having the wildcard signature apply to all > > UTXOs that are of a standard form and paid to a particular address, and > be > > a signature of some kind of message to that effect. I imagine the cost > of > > re-scanning the UTXO set to find them all would justify a special extra > > mining fee for any transaction that used this opcode. > > > > Please be blunt about any of my own misunderstandings that this email > makes > > clear. > > > > On Tue, Nov 24, 2015 at 1:51 PM, Bryan Bishop via bitcoin-dev < > > bitcoin-dev@lists•linuxfoundation.org> wrote: > > > >> On Tue, Nov 24, 2015 at 11:34 AM, Chris Priest via bitcoin-dev < > >> bitcoin-dev@lists•linuxfoundation.org> wrote: > >> > >>> **OP_CHECKWILDCARDSIGVERIFY** > >> > >> > >> Some (minor) discussion of this idea in -wizards earlier today starting > >> near near "09:50" (apologies for having no anchor links): > >> http://gnusha.org/bitcoin-wizards/2015-11-24.log > >> > >> - Bryan > >> http://heybryan.org/ > >> 1 512 203 0507 > >> > >> _______________________________________________ > >> bitcoin-dev mailing list > >> bitcoin-dev@lists•linuxfoundation.org > >> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > >> > >> > > > > > > -- > > I like to provide some work at no charge to prove my value. Do you need a > > techie? > > I own Litmocracy <http://www.litmocracy.com> and Meme Racing > > <http://www.memeracing.net> (in alpha). > > I'm the webmaster for The Voluntaryist <http://www.voluntaryist.com> > which > > now accepts Bitcoin. > > I also code for The Dollar Vigilante <http://dollarvigilante.com/>. > > "He ought to find it more profitable to play by the rules" - Satoshi > > Nakamoto > > > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists•linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > [-- Attachment #2: Type: text/html, Size: 5754 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [bitcoin-dev] OP_CHECKWILDCARDSIGVERIFY or "Wildcard Inputs" or "Coalescing Transactions" 2015-11-25 0:38 ` Jannes Faber @ 2015-11-25 1:26 ` Chris Priest 2015-11-25 14:16 ` Erik 0 siblings, 1 reply; 11+ messages in thread From: Chris Priest @ 2015-11-25 1:26 UTC (permalink / raw) To: Jannes Faber; +Cc: Bitcoin Dev 1. Technically is it promoting address reuse, but in this case, I think it's OK. The primary purpose of a coalescing transaction is to clear out *all* funds associated with one address and send them to another address (belonging to the same owner). If you coalesce the inputs to the same address over and over again, you an do that, but you'll run the risk of leaking your private key. 2. I see these transactions being broadcast in the background when the user is not planning on sending or receiving any payments. By the time the wallet user wants to spend funds from the address, the coalescing transaction should be sufficiently deep enough in the blockchain to avoid re-org tomfoolery. Exchanges and payment processors who take in payments around the clock will probably never use these transactions, at least not on "live" addresses. 3. I never thought of that, but thats a benefit too! On 11/24/15, Jannes Faber via bitcoin-dev <bitcoin-dev@lists•linuxfoundation.org> wrote: > Few issues I can think of: > > 1. In its basic form this encourages address reuse. Unless the wildcard can > be constructed such that it can match a whole branch of an HD wallet. > Although I guess that would tie all those addresses together making HD moot > to begin with. > > 2. Sounds pretty dangerous during reorgs. Maybe such a transaction should > include a block height which indicates the maximum block that any utxo can > match. With the requirement that the specified block height is at least 100 > blocks in the past. Maybe add a minimum block height as well to prevent > unnecessary scanning (with the requirement that at least one utxo must be > in that minimum block). > > 3. Seems like a nice way to the reduce utxo set. But hard to say how > effective it would really be. > On 25 Nov 2015 12:48 a.m., "Chris Priest via bitcoin-dev" < > bitcoin-dev@lists•linuxfoundation.org> wrote: > >> > This idea could be applied by having the wildcard signature apply to >> > all >> > UTXOs that are of a standard form and paid to a particular address, and >> be >> > a signature of some kind of message to that effect. >> >> I think this is true. Not *all* transactions will be able to match the >> wildcard. For instance if someone sent some crazy smart contract tx to >> your address, the script associated with that tx will be such that it >> will not apply to the wildcard. Most "vanilla" utxos that I've seen >> have the formula: OP_DUP OP_HASH160 [a hash corresponding to your >> address] OP_EQUALVERIFY OP_CHECKSIG". Just UTXOs in that form could >> apply to the wildcard. >> >> On 11/24/15, Dave Scotese via bitcoin-dev >> <bitcoin-dev@lists•linuxfoundation.org> wrote: >> > What is required to spend bitcoin is that input be provided to the UTXO >> > script that causes it to return true. What Chris is proposing breaks >> > the >> > programmatic nature of the requirement, replacing it with a requirement >> > that the secret be known. Granted, the secret is the only requirement >> > in >> > most cases, but there is no built-in assumption that the script always >> > requires only that secret. >> > >> > This idea could be applied by having the wildcard signature apply to >> > all >> > UTXOs that are of a standard form and paid to a particular address, and >> be >> > a signature of some kind of message to that effect. I imagine the cost >> of >> > re-scanning the UTXO set to find them all would justify a special extra >> > mining fee for any transaction that used this opcode. >> > >> > Please be blunt about any of my own misunderstandings that this email >> makes >> > clear. >> > >> > On Tue, Nov 24, 2015 at 1:51 PM, Bryan Bishop via bitcoin-dev < >> > bitcoin-dev@lists•linuxfoundation.org> wrote: >> > >> >> On Tue, Nov 24, 2015 at 11:34 AM, Chris Priest via bitcoin-dev < >> >> bitcoin-dev@lists•linuxfoundation.org> wrote: >> >> >> >>> **OP_CHECKWILDCARDSIGVERIFY** >> >> >> >> >> >> Some (minor) discussion of this idea in -wizards earlier today >> >> starting >> >> near near "09:50" (apologies for having no anchor links): >> >> http://gnusha.org/bitcoin-wizards/2015-11-24.log >> >> >> >> - Bryan >> >> http://heybryan.org/ >> >> 1 512 203 0507 >> >> >> >> _______________________________________________ >> >> bitcoin-dev mailing list >> >> bitcoin-dev@lists•linuxfoundation.org >> >> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev >> >> >> >> >> > >> > >> > -- >> > I like to provide some work at no charge to prove my value. Do you need >> > a >> > techie? >> > I own Litmocracy <http://www.litmocracy.com> and Meme Racing >> > <http://www.memeracing.net> (in alpha). >> > I'm the webmaster for The Voluntaryist <http://www.voluntaryist.com> >> which >> > now accepts Bitcoin. >> > I also code for The Dollar Vigilante <http://dollarvigilante.com/>. >> > "He ought to find it more profitable to play by the rules" - Satoshi >> > Nakamoto >> > >> _______________________________________________ >> bitcoin-dev mailing list >> bitcoin-dev@lists•linuxfoundation.org >> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev >> > ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [bitcoin-dev] OP_CHECKWILDCARDSIGVERIFY or "Wildcard Inputs" or "Coalescing Transactions" 2015-11-25 1:26 ` Chris Priest @ 2015-11-25 14:16 ` Erik 2015-11-25 15:41 ` Trevin Hofmann 2015-11-25 17:03 ` Dave Scotese 0 siblings, 2 replies; 11+ messages in thread From: Erik @ 2015-11-25 14:16 UTC (permalink / raw) To: bitcoin-dev -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Nice idea. I see it as an important feature because of several reasons: Considering the website example, where most websites uses static content, a bitcoin address could accumulate a dozen of transactions before the webmaster changes the address to a new one. Also consider a QR-code address printed on paper. That address is also prone to multiple payments, which could be several small ones. You ask someone to pay an amount of BTC. That person would be someone that want you to actually don't get any money at all, so instead of sending one payment, the person sends a lot of small TXes. It costs a lot more to achieve this, but that doesn't bother the person sending the transactions. What you see is the transactions to the address you've agreed sum up to the amount you asked for. When you later try to spend it, you can't because of that the size of all UXTOs is too high to even overcome the tx fee. If you use a wildcard transaction to bake them together into one UXTO, you will not need to pay more than just one tx fee to solve the problem you've got. Also the network will benefit from this because the alternative is to not spend those UXTOs at all because it costs more than it earns, leaving lots of UXTOs in the databases. Some problems to consider is: * Which addresses should be involved in a wildcard TX. * How to not make it repeatable or delayed so that UXTOs not intended to be in that TX wouldn't be included. * How to make it impossible to sign an wildcard TX with a future date. * How to limit outputs so they not are in risk being double-spent. * How to guarantee that the output is actually calculated from all the inputs involved and not less, making insane TX fees available. I could see possible solutions to this problems: * Using the highest block height number of transactions to include or maybe better, the UXTO of one transaction destined to that address involved in that block - that implies collecting all UXTOs in that block. * Using a signature that includes the date. To let it be present more times in the blockchain requires another timestamp that is newer than a wildcard TX already existing in the blockchain. Also make the transaction invalid to put in a block if the timestamp is behind a certain time or in the future. * Using the coinbase UXTO or the block hash from the latest block as proof that the transaction isn't created earlier than that. Also makes the wildcard TX invalid if that block isn't part of the blockchain anymore. This also have a secondary effect of certifying the blockchain itself making it more difficult to fork it from far behind because it will effectively remove all transactions depending on a UXTO including this type of certification. * Either using a priority like way to determine what are being left to wildcard in a block - all transactions spending UXTOs of that address is removed before the wildcard TX if they occurs in the same block. Either it is possible to set a rule that if a wildcard TX exists in one block, it is invalid to include other UXTOs that is to be be included in the wildcard from the same address in the same block. (Classic double-spending rule) * Using a special form of output specifying only one destination address/script and the amount of fees to pay. If the amount of fees could be payed, then the rest will be sent to the destination address. This covers intentional delaying and also discourage forking the blockchain by miners to making the signature UXTO appear later than more recent transaction in a new fork to collect the later txes as fee. This transaction type would in fact look like a time-limited offer to the network to reduce the UXTO set of an address. I guess some miners will then use a logic that prefers this types of TXes even if they are low-fee because, if they removes lots of UXTOs, they benefits the network. Sincerely, Erik. Den 2015-11-25 kl. 02:26, skrev Chris Priest via bitcoin-dev: > 1. Technically is it promoting address reuse, but in this case, I > think it's OK. The primary purpose of a coalescing transaction is to > clear out *all* funds associated with one address and send them to > another address (belonging to the same owner). If you coalesce the > inputs to the same address over and over again, you an do that, but > you'll run the risk of leaking your private key. > > 2. I see these transactions being broadcast in the background when the > user is not planning on sending or receiving any payments. By the time > the wallet user wants to spend funds from the address, the coalescing > transaction should be sufficiently deep enough in the blockchain to > avoid re-org tomfoolery. Exchanges and payment processors who take in > payments around the clock will probably never use these transactions, > at least not on "live" addresses. > > 3. I never thought of that, but thats a benefit too! > > On 11/24/15, Jannes Faber via bitcoin-dev > <bitcoin-dev@lists•linuxfoundation.org> wrote: >> Few issues I can think of: >> >> 1. In its basic form this encourages address reuse. Unless the wildcard can >> be constructed such that it can match a whole branch of an HD wallet. >> Although I guess that would tie all those addresses together making HD moot >> to begin with. >> >> 2. Sounds pretty dangerous during reorgs. Maybe such a transaction should >> include a block height which indicates the maximum block that any utxo can >> match. With the requirement that the specified block height is at least 100 >> blocks in the past. Maybe add a minimum block height as well to prevent >> unnecessary scanning (with the requirement that at least one utxo must be >> in that minimum block). >> >> 3. Seems like a nice way to the reduce utxo set. But hard to say how >> effective it would really be. >> On 25 Nov 2015 12:48 a.m., "Chris Priest via bitcoin-dev" < >> bitcoin-dev@lists•linuxfoundation.org> wrote: >> >>>> This idea could be applied by having the wildcard signature apply to >>>> all >>>> UTXOs that are of a standard form and paid to a particular address, and >>> be >>>> a signature of some kind of message to that effect. >>> >>> I think this is true. Not *all* transactions will be able to match the >>> wildcard. For instance if someone sent some crazy smart contract tx to >>> your address, the script associated with that tx will be such that it >>> will not apply to the wildcard. Most "vanilla" utxos that I've seen >>> have the formula: OP_DUP OP_HASH160 [a hash corresponding to your >>> address] OP_EQUALVERIFY OP_CHECKSIG". Just UTXOs in that form could >>> apply to the wildcard. >>> >>> On 11/24/15, Dave Scotese via bitcoin-dev >>> <bitcoin-dev@lists•linuxfoundation.org> wrote: >>>> What is required to spend bitcoin is that input be provided to the UTXO >>>> script that causes it to return true. What Chris is proposing breaks >>>> the >>>> programmatic nature of the requirement, replacing it with a requirement >>>> that the secret be known. Granted, the secret is the only requirement >>>> in >>>> most cases, but there is no built-in assumption that the script always >>>> requires only that secret. >>>> >>>> This idea could be applied by having the wildcard signature apply to >>>> all >>>> UTXOs that are of a standard form and paid to a particular address, and >>> be >>>> a signature of some kind of message to that effect. I imagine the cost >>> of >>>> re-scanning the UTXO set to find them all would justify a special extra >>>> mining fee for any transaction that used this opcode. >>>> >>>> Please be blunt about any of my own misunderstandings that this email >>> makes >>>> clear. >>>> >>>> On Tue, Nov 24, 2015 at 1:51 PM, Bryan Bishop via bitcoin-dev < >>>> bitcoin-dev@lists•linuxfoundation.org> wrote: >>>> >>>>> On Tue, Nov 24, 2015 at 11:34 AM, Chris Priest via bitcoin-dev < >>>>> bitcoin-dev@lists•linuxfoundation.org> wrote: >>>>> >>>>>> **OP_CHECKWILDCARDSIGVERIFY** >>>>> >>>>> >>>>> Some (minor) discussion of this idea in -wizards earlier today >>>>> starting >>>>> near near "09:50" (apologies for having no anchor links): >>>>> http://gnusha.org/bitcoin-wizards/2015-11-24.log >>>>> >>>>> - Bryan >>>>> http://heybryan.org/ >>>>> 1 512 203 0507 >>>>> >>>>> _______________________________________________ >>>>> bitcoin-dev mailing list >>>>> bitcoin-dev@lists•linuxfoundation.org >>>>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev >>>>> >>>>> >>>> >>>> >>>> -- >>>> I like to provide some work at no charge to prove my value. Do you need >>>> a >>>> techie? >>>> I own Litmocracy <http://www.litmocracy.com> and Meme Racing >>>> <http://www.memeracing.net> (in alpha). >>>> I'm the webmaster for The Voluntaryist <http://www.voluntaryist.com> >>> which >>>> now accepts Bitcoin. >>>> I also code for The Dollar Vigilante <http://dollarvigilante.com/>. >>>> "He ought to find it more profitable to play by the rules" - Satoshi >>>> Nakamoto >>>> >>> _______________________________________________ >>> bitcoin-dev mailing list >>> bitcoin-dev@lists•linuxfoundation.org >>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev >>> >> > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists•linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJWVcKuAAoJEJ51csApon2ofiYP/15DXthFvNg9pBPOaaboGOh1 DhN7R3SXnt4PTLygQGO3AkTRcDinQrZ0Q4GDLIgrOkaKJ4yr6FtnoEYGORQSfFkx 946eWtqkR4+IJi7gYIIn1yOfFjWKUp9l4OOWBA8Rxsn0tZUAQPXzf2f+dxAaj0Gd fLrftYvK1XJ8BolhwNfonJ193RJGFynQfWqZ+XeQQMS5LW23RpQLyI26f495MPHG Wug7M/Aq50JrJDe1OyhjnnjYxNV6Gdbg9o3YIdj2gaOsBKHzsPK+LjcLCdRqD/OI TBwmwiI4vrOl3HzvtucHxQqnaP43wubydVhPfmjG97tDaj2cVLjadc17e77PzCVI 8N21oVIWDzyW6y14REoo1Zs4A9ALpHjXAGWdls71eP1NIFcfdFAJWhk2/giisw8o ZsQTgq2mUHS+n4q3NjFEwGxS011yADE3Uf3ryjuTjp3HVQf3lZxn4E4Z7z/4gkXm /h/3Ln7PkjEmOqp9htgHcYW7q5goeJzV0xNDBoY9wvOlJQcAh6nTiS4SJEiFJvXU xVZIGZsisrdW/1CfcszOi7KFGaaV1VlAXQnuJHj1I3dJ2r68yi5TQk6voMNFprEz 2R4zuZKjIoH79rOjDV8l6XBIU1Kh92GEzCFlTicfvnAoa853fGZt+V/77ralftJW E6sERK8uG8S3KdBSVQ7K =1xdi -----END PGP SIGNATURE----- ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [bitcoin-dev] OP_CHECKWILDCARDSIGVERIFY or "Wildcard Inputs" or "Coalescing Transactions" 2015-11-25 14:16 ` Erik @ 2015-11-25 15:41 ` Trevin Hofmann 2015-11-25 17:03 ` Dave Scotese 1 sibling, 0 replies; 11+ messages in thread From: Trevin Hofmann @ 2015-11-25 15:41 UTC (permalink / raw) To: Erik; +Cc: bitcoin-dev [-- Attachment #1: Type: text/plain, Size: 11222 bytes --] > Considering the website example, where most websites uses static content, a bitcoin address could accumulate a dozen of transactions before the webmaster changes the address to a new one. Would this use case be a better match for something such as stealth addresses or hierarchical deterministic addresses? Trevin Hofmann On Nov 25, 2015 8:16 AM, "Erik via bitcoin-dev" < bitcoin-dev@lists•linuxfoundation.org> wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > > Nice idea. I see it as an important feature because of several reasons: > > Considering the website example, where most websites uses static > content, a bitcoin address could accumulate a dozen of transactions > before the webmaster changes the address to a new one. > > Also consider a QR-code address printed on paper. That address is also > prone to multiple payments, which could be several small ones. > > You ask someone to pay an amount of BTC. That person would be someone > that want you to actually don't get any money at all, so instead of > sending one payment, the person sends a lot of small TXes. It costs a > lot more to achieve this, but that doesn't bother the person sending the > transactions. What you see is the transactions to the address you've > agreed sum up to the amount you asked for. When you later try to spend > it, you can't because of that the size of all UXTOs is too high to even > overcome the tx fee. > > If you use a wildcard transaction to bake them together into one UXTO, > you will not need to pay more than just one tx fee to solve the problem > you've got. Also the network will benefit from this because the > alternative is to not spend those UXTOs at all because it costs more > than it earns, leaving lots of UXTOs in the databases. > > Some problems to consider is: > * Which addresses should be involved in a wildcard TX. > * How to not make it repeatable or delayed so that UXTOs not intended to > be in that TX wouldn't be included. > * How to make it impossible to sign an wildcard TX with a future date. > * How to limit outputs so they not are in risk being double-spent. > * How to guarantee that the output is actually calculated from all the > inputs involved and not less, making insane TX fees available. > > I could see possible solutions to this problems: > * Using the highest block height number of transactions to include or > maybe better, the UXTO of one transaction destined to that address > involved in that block - that implies collecting all UXTOs in that block. > * Using a signature that includes the date. To let it be present more > times in the blockchain requires another timestamp that is newer than a > wildcard TX already existing in the blockchain. Also make the > transaction invalid to put in a block if the timestamp is behind a > certain time or in the future. > * Using the coinbase UXTO or the block hash from the latest block as > proof that the transaction isn't created earlier than that. Also makes > the wildcard TX invalid if that block isn't part of the blockchain > anymore. This also have a secondary effect of certifying the blockchain > itself making it more difficult to fork it from far behind because it > will effectively remove all transactions depending on a UXTO including > this type of certification. > * Either using a priority like way to determine what are being left to > wildcard in a block - all transactions spending UXTOs of that address is > removed before the wildcard TX if they occurs in the same block. Either > it is possible to set a rule that if a wildcard TX exists in one block, > it is invalid to include other UXTOs that is to be be included in the > wildcard from the same address in the same block. (Classic > double-spending rule) > * Using a special form of output specifying only one destination > address/script and the amount of fees to pay. If the amount of fees > could be payed, then the rest will be sent to the destination address. > This covers intentional delaying and also discourage forking the > blockchain by miners to making the signature UXTO appear later than more > recent transaction in a new fork to collect the later txes as fee. > > This transaction type would in fact look like a time-limited offer to > the network to reduce the UXTO set of an address. I guess some miners > will then use a logic that prefers this types of TXes even if they are > low-fee because, if they removes lots of UXTOs, they benefits the network. > > Sincerely, > Erik. > > Den 2015-11-25 kl. 02:26, skrev Chris Priest via bitcoin-dev: > > 1. Technically is it promoting address reuse, but in this case, I > > think it's OK. The primary purpose of a coalescing transaction is to > > clear out *all* funds associated with one address and send them to > > another address (belonging to the same owner). If you coalesce the > > inputs to the same address over and over again, you an do that, but > > you'll run the risk of leaking your private key. > > > > 2. I see these transactions being broadcast in the background when the > > user is not planning on sending or receiving any payments. By the time > > the wallet user wants to spend funds from the address, the coalescing > > transaction should be sufficiently deep enough in the blockchain to > > avoid re-org tomfoolery. Exchanges and payment processors who take in > > payments around the clock will probably never use these transactions, > > at least not on "live" addresses. > > > > 3. I never thought of that, but thats a benefit too! > > > > On 11/24/15, Jannes Faber via bitcoin-dev > > <bitcoin-dev@lists•linuxfoundation.org> wrote: > >> Few issues I can think of: > >> > >> 1. In its basic form this encourages address reuse. Unless the > wildcard can > >> be constructed such that it can match a whole branch of an HD wallet. > >> Although I guess that would tie all those addresses together making > HD moot > >> to begin with. > >> > >> 2. Sounds pretty dangerous during reorgs. Maybe such a transaction > should > >> include a block height which indicates the maximum block that any > utxo can > >> match. With the requirement that the specified block height is at > least 100 > >> blocks in the past. Maybe add a minimum block height as well to prevent > >> unnecessary scanning (with the requirement that at least one utxo must > be > >> in that minimum block). > >> > >> 3. Seems like a nice way to the reduce utxo set. But hard to say how > >> effective it would really be. > >> On 25 Nov 2015 12:48 a.m., "Chris Priest via bitcoin-dev" < > >> bitcoin-dev@lists•linuxfoundation.org> wrote: > >> > >>>> This idea could be applied by having the wildcard signature apply to > >>>> all > >>>> UTXOs that are of a standard form and paid to a particular address, > and > >>> be > >>>> a signature of some kind of message to that effect. > >>> > >>> I think this is true. Not *all* transactions will be able to match the > >>> wildcard. For instance if someone sent some crazy smart contract tx to > >>> your address, the script associated with that tx will be such that it > >>> will not apply to the wildcard. Most "vanilla" utxos that I've seen > >>> have the formula: OP_DUP OP_HASH160 [a hash corresponding to your > >>> address] OP_EQUALVERIFY OP_CHECKSIG". Just UTXOs in that form could > >>> apply to the wildcard. > >>> > >>> On 11/24/15, Dave Scotese via bitcoin-dev > >>> <bitcoin-dev@lists•linuxfoundation.org> wrote: > >>>> What is required to spend bitcoin is that input be provided to the > UTXO > >>>> script that causes it to return true. What Chris is proposing breaks > >>>> the > >>>> programmatic nature of the requirement, replacing it with a > requirement > >>>> that the secret be known. Granted, the secret is the only requirement > >>>> in > >>>> most cases, but there is no built-in assumption that the script always > >>>> requires only that secret. > >>>> > >>>> This idea could be applied by having the wildcard signature apply to > >>>> all > >>>> UTXOs that are of a standard form and paid to a particular address, > and > >>> be > >>>> a signature of some kind of message to that effect. I imagine the > cost > >>> of > >>>> re-scanning the UTXO set to find them all would justify a special > extra > >>>> mining fee for any transaction that used this opcode. > >>>> > >>>> Please be blunt about any of my own misunderstandings that this email > >>> makes > >>>> clear. > >>>> > >>>> On Tue, Nov 24, 2015 at 1:51 PM, Bryan Bishop via bitcoin-dev < > >>>> bitcoin-dev@lists•linuxfoundation.org> wrote: > >>>> > >>>>> On Tue, Nov 24, 2015 at 11:34 AM, Chris Priest via bitcoin-dev < > >>>>> bitcoin-dev@lists•linuxfoundation.org> wrote: > >>>>> > >>>>>> **OP_CHECKWILDCARDSIGVERIFY** > >>>>> > >>>>> > >>>>> Some (minor) discussion of this idea in -wizards earlier today > >>>>> starting > >>>>> near near "09:50" (apologies for having no anchor links): > >>>>> http://gnusha.org/bitcoin-wizards/2015-11-24.log > >>>>> > >>>>> - Bryan > >>>>> http://heybryan.org/ > >>>>> 1 512 203 0507 > >>>>> > >>>>> _______________________________________________ > >>>>> bitcoin-dev mailing list > >>>>> bitcoin-dev@lists•linuxfoundation.org > >>>>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > >>>>> > >>>>> > >>>> > >>>> > >>>> -- > >>>> I like to provide some work at no charge to prove my value. Do you > need > >>>> a > >>>> techie? > >>>> I own Litmocracy <http://www.litmocracy.com> and Meme Racing > >>>> <http://www.memeracing.net> (in alpha). > >>>> I'm the webmaster for The Voluntaryist <http://www.voluntaryist.com> > >>> which > >>>> now accepts Bitcoin. > >>>> I also code for The Dollar Vigilante <http://dollarvigilante.com/>. > >>>> "He ought to find it more profitable to play by the rules" - Satoshi > >>>> Nakamoto > >>>> > >>> _______________________________________________ > >>> bitcoin-dev mailing list > >>> bitcoin-dev@lists•linuxfoundation.org > >>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > >>> > >> > > _______________________________________________ > > bitcoin-dev mailing list > > bitcoin-dev@lists•linuxfoundation.org > > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v2.0.22 (GNU/Linux) > > iQIcBAEBAgAGBQJWVcKuAAoJEJ51csApon2ofiYP/15DXthFvNg9pBPOaaboGOh1 > DhN7R3SXnt4PTLygQGO3AkTRcDinQrZ0Q4GDLIgrOkaKJ4yr6FtnoEYGORQSfFkx > 946eWtqkR4+IJi7gYIIn1yOfFjWKUp9l4OOWBA8Rxsn0tZUAQPXzf2f+dxAaj0Gd > fLrftYvK1XJ8BolhwNfonJ193RJGFynQfWqZ+XeQQMS5LW23RpQLyI26f495MPHG > Wug7M/Aq50JrJDe1OyhjnnjYxNV6Gdbg9o3YIdj2gaOsBKHzsPK+LjcLCdRqD/OI > TBwmwiI4vrOl3HzvtucHxQqnaP43wubydVhPfmjG97tDaj2cVLjadc17e77PzCVI > 8N21oVIWDzyW6y14REoo1Zs4A9ALpHjXAGWdls71eP1NIFcfdFAJWhk2/giisw8o > ZsQTgq2mUHS+n4q3NjFEwGxS011yADE3Uf3ryjuTjp3HVQf3lZxn4E4Z7z/4gkXm > /h/3Ln7PkjEmOqp9htgHcYW7q5goeJzV0xNDBoY9wvOlJQcAh6nTiS4SJEiFJvXU > xVZIGZsisrdW/1CfcszOi7KFGaaV1VlAXQnuJHj1I3dJ2r68yi5TQk6voMNFprEz > 2R4zuZKjIoH79rOjDV8l6XBIU1Kh92GEzCFlTicfvnAoa853fGZt+V/77ralftJW > E6sERK8uG8S3KdBSVQ7K > =1xdi > -----END PGP SIGNATURE----- > > > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists•linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > [-- Attachment #2: Type: text/html, Size: 15048 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [bitcoin-dev] OP_CHECKWILDCARDSIGVERIFY or "Wildcard Inputs" or "Coalescing Transactions" 2015-11-25 14:16 ` Erik 2015-11-25 15:41 ` Trevin Hofmann @ 2015-11-25 17:03 ` Dave Scotese 1 sibling, 0 replies; 11+ messages in thread From: Dave Scotese @ 2015-11-25 17:03 UTC (permalink / raw) To: Erik; +Cc: Bitcoin Dev [-- Attachment #1: Type: text/plain, Size: 12145 bytes --] The message could specify: { stib: 0x01, TxnCount: (# of entries in the Indexes array) Indexes: [{BLK: Block#,Txns:[TxIndex,TxIndex,...]},{BLK: Block#,Txns:[...]}], NewUTXO: (The script that will spend these coins) } *stib *is a Script Template Index Bitfield: Must (currently) be the byte 0x01, to indicate the "vanilla" script Chris identified. If other scripts appear to fit the bill in the future, they can be assigned to other bits. *Indexes *is a list of pairs that identify a block by its height and a list of indexes into the block. This puts the onus on the transactor to identify all the inputs instead of requiring the miner to scan for them. If block heights and transaction indexes are 32-bit integers, this reduces the per-input size cost by at least 100 bytes, if I did my math right. On Wed, Nov 25, 2015 at 6:16 AM, Erik via bitcoin-dev < bitcoin-dev@lists•linuxfoundation.org> wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > > Nice idea. I see it as an important feature because of several reasons: > > Considering the website example, where most websites uses static > content, a bitcoin address could accumulate a dozen of transactions > before the webmaster changes the address to a new one. > > Also consider a QR-code address printed on paper. That address is also > prone to multiple payments, which could be several small ones. > > You ask someone to pay an amount of BTC. That person would be someone > that want you to actually don't get any money at all, so instead of > sending one payment, the person sends a lot of small TXes. It costs a > lot more to achieve this, but that doesn't bother the person sending the > transactions. What you see is the transactions to the address you've > agreed sum up to the amount you asked for. When you later try to spend > it, you can't because of that the size of all UXTOs is too high to even > overcome the tx fee. > > If you use a wildcard transaction to bake them together into one UXTO, > you will not need to pay more than just one tx fee to solve the problem > you've got. Also the network will benefit from this because the > alternative is to not spend those UXTOs at all because it costs more > than it earns, leaving lots of UXTOs in the databases. > > Some problems to consider is: > * Which addresses should be involved in a wildcard TX. > * How to not make it repeatable or delayed so that UXTOs not intended to > be in that TX wouldn't be included. > * How to make it impossible to sign an wildcard TX with a future date. > * How to limit outputs so they not are in risk being double-spent. > * How to guarantee that the output is actually calculated from all the > inputs involved and not less, making insane TX fees available. > > I could see possible solutions to this problems: > * Using the highest block height number of transactions to include or > maybe better, the UXTO of one transaction destined to that address > involved in that block - that implies collecting all UXTOs in that block. > * Using a signature that includes the date. To let it be present more > times in the blockchain requires another timestamp that is newer than a > wildcard TX already existing in the blockchain. Also make the > transaction invalid to put in a block if the timestamp is behind a > certain time or in the future. > * Using the coinbase UXTO or the block hash from the latest block as > proof that the transaction isn't created earlier than that. Also makes > the wildcard TX invalid if that block isn't part of the blockchain > anymore. This also have a secondary effect of certifying the blockchain > itself making it more difficult to fork it from far behind because it > will effectively remove all transactions depending on a UXTO including > this type of certification. > * Either using a priority like way to determine what are being left to > wildcard in a block - all transactions spending UXTOs of that address is > removed before the wildcard TX if they occurs in the same block. Either > it is possible to set a rule that if a wildcard TX exists in one block, > it is invalid to include other UXTOs that is to be be included in the > wildcard from the same address in the same block. (Classic > double-spending rule) > * Using a special form of output specifying only one destination > address/script and the amount of fees to pay. If the amount of fees > could be payed, then the rest will be sent to the destination address. > This covers intentional delaying and also discourage forking the > blockchain by miners to making the signature UXTO appear later than more > recent transaction in a new fork to collect the later txes as fee. > > This transaction type would in fact look like a time-limited offer to > the network to reduce the UXTO set of an address. I guess some miners > will then use a logic that prefers this types of TXes even if they are > low-fee because, if they removes lots of UXTOs, they benefits the network. > > Sincerely, > Erik. > > Den 2015-11-25 kl. 02:26, skrev Chris Priest via bitcoin-dev: > > 1. Technically is it promoting address reuse, but in this case, I > > think it's OK. The primary purpose of a coalescing transaction is to > > clear out *all* funds associated with one address and send them to > > another address (belonging to the same owner). If you coalesce the > > inputs to the same address over and over again, you an do that, but > > you'll run the risk of leaking your private key. > > > > 2. I see these transactions being broadcast in the background when the > > user is not planning on sending or receiving any payments. By the time > > the wallet user wants to spend funds from the address, the coalescing > > transaction should be sufficiently deep enough in the blockchain to > > avoid re-org tomfoolery. Exchanges and payment processors who take in > > payments around the clock will probably never use these transactions, > > at least not on "live" addresses. > > > > 3. I never thought of that, but thats a benefit too! > > > > On 11/24/15, Jannes Faber via bitcoin-dev > > <bitcoin-dev@lists•linuxfoundation.org> wrote: > >> Few issues I can think of: > >> > >> 1. In its basic form this encourages address reuse. Unless the > wildcard can > >> be constructed such that it can match a whole branch of an HD wallet. > >> Although I guess that would tie all those addresses together making > HD moot > >> to begin with. > >> > >> 2. Sounds pretty dangerous during reorgs. Maybe such a transaction > should > >> include a block height which indicates the maximum block that any > utxo can > >> match. With the requirement that the specified block height is at > least 100 > >> blocks in the past. Maybe add a minimum block height as well to prevent > >> unnecessary scanning (with the requirement that at least one utxo must > be > >> in that minimum block). > >> > >> 3. Seems like a nice way to the reduce utxo set. But hard to say how > >> effective it would really be. > >> On 25 Nov 2015 12:48 a.m., "Chris Priest via bitcoin-dev" < > >> bitcoin-dev@lists•linuxfoundation.org> wrote: > >> > >>>> This idea could be applied by having the wildcard signature apply to > >>>> all > >>>> UTXOs that are of a standard form and paid to a particular address, > and > >>> be > >>>> a signature of some kind of message to that effect. > >>> > >>> I think this is true. Not *all* transactions will be able to match the > >>> wildcard. For instance if someone sent some crazy smart contract tx to > >>> your address, the script associated with that tx will be such that it > >>> will not apply to the wildcard. Most "vanilla" utxos that I've seen > >>> have the formula: OP_DUP OP_HASH160 [a hash corresponding to your > >>> address] OP_EQUALVERIFY OP_CHECKSIG". Just UTXOs in that form could > >>> apply to the wildcard. > >>> > >>> On 11/24/15, Dave Scotese via bitcoin-dev > >>> <bitcoin-dev@lists•linuxfoundation.org> wrote: > >>>> What is required to spend bitcoin is that input be provided to the > UTXO > >>>> script that causes it to return true. What Chris is proposing breaks > >>>> the > >>>> programmatic nature of the requirement, replacing it with a > requirement > >>>> that the secret be known. Granted, the secret is the only requirement > >>>> in > >>>> most cases, but there is no built-in assumption that the script always > >>>> requires only that secret. > >>>> > >>>> This idea could be applied by having the wildcard signature apply to > >>>> all > >>>> UTXOs that are of a standard form and paid to a particular address, > and > >>> be > >>>> a signature of some kind of message to that effect. I imagine the > cost > >>> of > >>>> re-scanning the UTXO set to find them all would justify a special > extra > >>>> mining fee for any transaction that used this opcode. > >>>> > >>>> Please be blunt about any of my own misunderstandings that this email > >>> makes > >>>> clear. > >>>> > >>>> On Tue, Nov 24, 2015 at 1:51 PM, Bryan Bishop via bitcoin-dev < > >>>> bitcoin-dev@lists•linuxfoundation.org> wrote: > >>>> > >>>>> On Tue, Nov 24, 2015 at 11:34 AM, Chris Priest via bitcoin-dev < > >>>>> bitcoin-dev@lists•linuxfoundation.org> wrote: > >>>>> > >>>>>> **OP_CHECKWILDCARDSIGVERIFY** > >>>>> > >>>>> > >>>>> Some (minor) discussion of this idea in -wizards earlier today > >>>>> starting > >>>>> near near "09:50" (apologies for having no anchor links): > >>>>> http://gnusha.org/bitcoin-wizards/2015-11-24.log > >>>>> > >>>>> - Bryan > >>>>> http://heybryan.org/ > >>>>> 1 512 203 0507 > >>>>> > >>>>> _______________________________________________ > >>>>> bitcoin-dev mailing list > >>>>> bitcoin-dev@lists•linuxfoundation.org > >>>>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > >>>>> > >>>>> > >>>> > >>>> > >>>> -- > >>>> I like to provide some work at no charge to prove my value. Do you > need > >>>> a > >>>> techie? > >>>> I own Litmocracy <http://www.litmocracy.com> and Meme Racing > >>>> <http://www.memeracing.net> (in alpha). > >>>> I'm the webmaster for The Voluntaryist <http://www.voluntaryist.com> > >>> which > >>>> now accepts Bitcoin. > >>>> I also code for The Dollar Vigilante <http://dollarvigilante.com/>. > >>>> "He ought to find it more profitable to play by the rules" - Satoshi > >>>> Nakamoto > >>>> > >>> _______________________________________________ > >>> bitcoin-dev mailing list > >>> bitcoin-dev@lists•linuxfoundation.org > >>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > >>> > >> > > _______________________________________________ > > bitcoin-dev mailing list > > bitcoin-dev@lists•linuxfoundation.org > > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v2.0.22 (GNU/Linux) > > iQIcBAEBAgAGBQJWVcKuAAoJEJ51csApon2ofiYP/15DXthFvNg9pBPOaaboGOh1 > DhN7R3SXnt4PTLygQGO3AkTRcDinQrZ0Q4GDLIgrOkaKJ4yr6FtnoEYGORQSfFkx > 946eWtqkR4+IJi7gYIIn1yOfFjWKUp9l4OOWBA8Rxsn0tZUAQPXzf2f+dxAaj0Gd > fLrftYvK1XJ8BolhwNfonJ193RJGFynQfWqZ+XeQQMS5LW23RpQLyI26f495MPHG > Wug7M/Aq50JrJDe1OyhjnnjYxNV6Gdbg9o3YIdj2gaOsBKHzsPK+LjcLCdRqD/OI > TBwmwiI4vrOl3HzvtucHxQqnaP43wubydVhPfmjG97tDaj2cVLjadc17e77PzCVI > 8N21oVIWDzyW6y14REoo1Zs4A9ALpHjXAGWdls71eP1NIFcfdFAJWhk2/giisw8o > ZsQTgq2mUHS+n4q3NjFEwGxS011yADE3Uf3ryjuTjp3HVQf3lZxn4E4Z7z/4gkXm > /h/3Ln7PkjEmOqp9htgHcYW7q5goeJzV0xNDBoY9wvOlJQcAh6nTiS4SJEiFJvXU > xVZIGZsisrdW/1CfcszOi7KFGaaV1VlAXQnuJHj1I3dJ2r68yi5TQk6voMNFprEz > 2R4zuZKjIoH79rOjDV8l6XBIU1Kh92GEzCFlTicfvnAoa853fGZt+V/77ralftJW > E6sERK8uG8S3KdBSVQ7K > =1xdi > -----END PGP SIGNATURE----- > > > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists•linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > -- I like to provide some work at no charge to prove my value. Do you need a techie? I own Litmocracy <http://www.litmocracy.com> and Meme Racing <http://www.memeracing.net> (in alpha). I'm the webmaster for The Voluntaryist <http://www.voluntaryist.com> which now accepts Bitcoin. I also code for The Dollar Vigilante <http://dollarvigilante.com/>. "He ought to find it more profitable to play by the rules" - Satoshi Nakamoto [-- Attachment #2: Type: text/html, Size: 16417 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2015-11-25 17:03 UTC | newest] Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2015-11-24 17:34 [bitcoin-dev] OP_CHECKWILDCARDSIGVERIFY or "Wildcard Inputs" or "Coalescing Transactions" Chris Priest 2015-11-24 20:32 ` Gavin Andresen 2015-11-24 21:01 ` Chris Priest 2015-11-24 21:51 ` Bryan Bishop 2015-11-24 23:28 ` Dave Scotese 2015-11-24 23:48 ` Chris Priest 2015-11-25 0:38 ` Jannes Faber 2015-11-25 1:26 ` Chris Priest 2015-11-25 14:16 ` Erik 2015-11-25 15:41 ` Trevin Hofmann 2015-11-25 17:03 ` Dave Scotese
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