|
Title: Blockchain security tracking/colored coins/smart contracts - short python script Post by: bitfair on October 10, 2012, 03:26:56 PM There are now many threads about "colored coins", "smart contracts" and otherwise tracking specific coins through the blockchain.
I have created a simple command-line Python program to handle tracking of "colored coins", "smart contracts" or "blockchain securities" in the blockchain. There are other approaches, and the one I have taken is very simple, but it is a working solution (primitively duct-taped and glued together). I also have not read gone into the details of the other approaches, so it is probably safe to say that the method I have created is completely incompatible with the other methods (which are probably much smarter too). But it is a live and implemented solution, which gives it an advantage over others. It is short, easy to modify and fun to play with. It might be useful for some adventurous security issuers who are looking for a solution now that GLBSE is shutting down. Full source: http://pastebin.com/hbUz0vS9 (http://pastebin.com/hbUz0vS9) Update Oct 15: The source code has been updated, the new version includes functions to pay dividends to holders of the colored coins. Also, it has been tested more thoroughly, and I have created a 12-step usage example that shows the current capabilities of the script. Update Oct 18: The source code has been updated, the new version includes the functions to include a transaction fee from an (uncolored!) address in your standard/satoshi-client wallet when transferring assets so that the transaction is more likely to confirm more quickly (command-line option -w <fee>, where <fee> is the fee you want to pay in BTC, e.g. -w 0.005 for half a bitcent). Also, the tracking of colored coins is now also believed to be compatible with other approaches for "order-based" tracking, such as the one used in killerstorm's modified Satoshi client (however, I still want to build up a bunch of test-cases to see if the clients interpret all the cases in the same way). Next, I think it is time to create ample test-cases, and tidy up the code - it has turned into a bit of a spaghetti-ball. Usage example: Code:
Planned features: - GUI Please be cautious when using it, but feel free to criticise, modify and contribute. And if you like it, support it: 1GsnaaAWYMb7yPwBQ19bSLLMTtsfSyjqg3. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: jl2012 on October 10, 2012, 04:19:41 PM There are now many threads about "colored coins", "smart contracts" and otherwise tracking specific coins through the blockchain. I think it is because the fail of GLBSE. The next generation of bitcoin security exchange will be colored-coin-based p2p system. The role of a centralized exchange (if any) is to facilitate bid/ask matching, to advertise IPO, and to rate the trustworthiness of security issuers. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: matthewh3 on October 10, 2012, 07:25:40 PM Can you automatically pay dividends to coloured coins?
Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: bitfair on October 10, 2012, 07:32:48 PM Can you automatically pay dividends to coloured coins? Not yet, but it will be relatively trivial to implement. The script already produces a list of "shareholders" (as represented by their bitcoin addresses) and the share that they own. From that, it's just a question of massaging the data to the right format and feeding it to the bitcoin json API. I will see if I have the time to implement it this week, and pastebin a newer version. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: matthewh3 on October 10, 2012, 07:37:00 PM Can you automatically pay dividends to coloured coins? Not yet, but it will be relatively trivial to implement. The script already produces a list of "shareholders" (as represented by their bitcoin addresses) and the share that they own. From that, it's just a question of massaging the data to the right format and feeding it to the bitcoin json API. I will see if I have the time to implement it this week, and pastebin a newer version. Cool, if you do I may use it for my asset. I'll see if I can organise you a donation for your work from shareholders if we use your client. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: bitfair on October 10, 2012, 07:50:32 PM I am planning to implement it such that dividends/coupons/whatever can be paid to the owners (proportional to their share, of course) from the wallet. It will be paid to the same address which is registered as the owner of the colored coins - but the receiver will need to be careful when spending the dividends, so it doesn't accidentally spend the transaction that represents the share. For that reason, I also need to implement routines to safely transfer the dividends from the address holding the colored coins and to another address.
Thanks for considering using it. It's more fun when someone finds it useful. But beware that it should be considered experimental at this stage (although as long as no private keys are lost, it shouldn't really be "dangerous" to try it). Also considering a simple GUI, that might lower the barriers to using it. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: socrates1024 on October 10, 2012, 08:05:01 PM Any idea what the asymptotic complexity is of this implementation? I'd be interested in the a) time, b) storage space, and c) transfer requirements, in terms of quantities such as 1) the number of tracked coins, 2) the number of transactions for each coin.
Also, it looks like your config file is not just a config file, but also is a stateful database that stores the current owner of each coin. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: matthewh3 on October 10, 2012, 08:13:46 PM Well we will probably wait until it is a bit more mature but I will put forward the idea that you get a donation from our shareholders.
Another question is does the whole blockchain need to be saved and how can I distribute more than one copy of this new coloured blockchain. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: bitfair on October 10, 2012, 08:29:05 PM Any idea what the asymptotic complexity is of this implementation? I'd be interested in the a) time, b) storage space, and c) transfer requirements, in terms of quantities such as 1) the number of tracked coins, 2) the number of transactions for each coin. Also, tt looks like your config file is not just a config file, but also is a stateful database that stores the current owner of each coin. Excellent questions, sir! It's a very crude script at the moment, following one of the pillars of "open source": release early, release often. (I guess the reason is that it gives others the chance to make and suggest improvements!) Complexity (answers pulled out of my hat without terribly much thinking, I might need to correct it later): a) Time: standard tree traversal time, O(n) where n is the number of nodes. In this case that means the number of transactions of the security that have been made since the root/ancestor transaction. In this implementation, the latency from accessing blockchain.info on the web will dominate (which it does to find out which transaction the coin was spent in next) - executed O(n) times. b) Storage: While traversing the blockchain, a stack depth of O(log(n)) will be kept in memory (many assumptions in this). After traversal, the leaf nodes are stored in the config file, so it is proportional to the amount of "owners" of the colored coins. And yes, you are quite right: in the spirit of simplicity and transparency over rigid correctness, all information is currently stored in the configuration file. (You may now commence your complaining:) Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: bitfair on October 10, 2012, 08:36:49 PM Well we will probably wait until it is a bit more mature but I will put forward the idea that you get a donation from our shareholders. Another question is does the whole blockchain need to be saved and how can I distribute more than one copy of this new coloured blockchain. There is no "colored blockchain", it uses only the standard bitcoin blockchain and tracks all the transactions in a chain starting at a particular given transaction. That a coin is "colored" only means that it can be traced (through the blockchain) to belong to a very specific transaction, chosen and named by yourself. And it simply makes sure that the transactions built by the script are formed in such a way that allows them to be tracked by the script. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: jgarzik on October 10, 2012, 09:31:31 PM There is no "colored blockchain", it uses only the standard bitcoin blockchain and tracks all the transactions in a chain starting at a particular given transaction. That a coin is "colored" only means that it can be traced (through the blockchain) to belong to a very specific transaction, chosen and named by yourself. True, however: a chain specifically for smart property could potentially keep bloat out of the main chain. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: bitfair on October 11, 2012, 11:15:36 AM True, however: a chain specifically for smart property could potentially keep bloat out of the main chain. I agree in principle, although I believe bloat from piggybacking on the main chain would be negligible in the bigger picture. In addition, a separate chain for smart property would also require separate mining, and mining requires some kind of compensation paid to the miners - and I haven't been able to think of any sensible "compensation scheme" that would make it worth their while. [But, by all means, don't let the discussion stop at my lack of imagination!] Edit: Currently testing dividend/coupon-payment function using the 1 BTC that was donated (thanks!), script will be updated when it appears to be working. And shortly after that, expect a "howto"/annotated example. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: markm on October 11, 2012, 03:13:43 PM Since coins can now be tracked, and thus need no longer be and maybe will no longer be fungible, we can devalue coins mined into the coinbase transactions of blocks where list of merged mined chains codes does not include our chain.
Maybe only people who try to buy securities will care, if no other chains also devalue those specific coins and their descendants, of course. But would the actual coins of a securities chain actually be worthless when uncoloured? Or would folk looking to colour them consider them worth buying? How many securitysatoshis would be mined per block in such a chain? When bitcoin catches on, how fabulously expensive is it going to be to have to pay for an actual bitcoin chain transaction every time you want to change which family-member controls the garage door opener or other smart-property? Might using one of the many commonly merged chains be more cost-effective when dealing with smart property smaller than, say, a small house or fancy vehicle? Would this use of the bitcoin chain be a better way of implementing domains, aliases, pseudonymous identities, keyrings and such than the ostensibly designed for the purpose namecoin? (Maybe namecoin was a silly clumsy ill thought out idea that overlooked this much more natural, elegant, effective approach?) -MarkM- Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: Andrew Vorobyov on October 11, 2012, 03:59:34 PM Post on github.com
Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: bitfair on October 11, 2012, 05:15:12 PM Post on github.com It's starting to push the limit for what can go into a single file - I will be considering putting it on github when it becomes necessary to split it into several files. (Probably pretty soon!) Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: yoniassia on October 11, 2012, 06:35:43 PM This is really great ! Can you explain the diff between your implementation and the main colored coins thread ? Would be great to merge coloring so there will be one standard.
Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: bitfair on October 11, 2012, 06:53:07 PM This is really great ! Can you explain the diff between your implementation and the main colored coins thread ? Would be great to merge coloring so there will be one standard. I'm not quite up-to-date on the main colored coins thread, so I'm afraid I can't explain it at the moment. Will read up on it, though, and see if our thoughts are compatible. In other news, a newer version is currently being tested, which allows paying of dividends/coupons/etc from your wallet to the addresses that hold the colored coins. However, progress has been stumped by a bug in blockchain.info (https://bitcointalk.org/index.php?topic=40264.msg1265405#msg1265405 (https://bitcointalk.org/index.php?topic=40264.msg1265405#msg1265405)). Either they will fix the bug in reasonable time, or I guess I will need to work around it (which would be tedious). Stay tuned! Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: killerstorm on October 11, 2012, 09:44:26 PM I guess the main difference is that we were focusing on allowing to have coins of multiple colors in same transaction, while this version doesn't allow it, comment in code:
Code: # This is because it is not possible to follow a colored coin across a transaction More fine-grained color tracking is needed to implement secure exchange: coins of different colors will be exchanged in one atomic transaction. Otherwise this script seems to be roughly equivalent to the prototype I've implemented about a month ago, in terms of coloring. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: yoniassia on October 12, 2012, 09:17:21 PM So can both coloring schemes be merged into one standard, can we define that standard ? Anything worth updating here ? ( no need to allow multi colors in one transaction in all scripts, simply means they can read only "pure colors").
Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: killerstorm on October 12, 2012, 11:40:37 PM Well, it is compatible with order-based coloring: if we have one input, it is always in correct order :)
But I don't think that having two versions (let's call them simple and complex) is a good idea: that would mean that if somebody makes a 'complex' transaction, those coins won't be visible in 'simple' version anymore. Forever: there is no way to repair it for 'simple' version. Also I think simple version should support at least 1 color + uncolored scheme. This would allow payment of transaction fees, buy/sell atomic transactions etc. There is no need to support more than one color in one transaction, but colored + uncolored is sort of necessary. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: yoniassia on October 13, 2012, 07:07:51 AM Could you suggest the code changes for this script to support order based ?
Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: killerstorm on October 13, 2012, 10:22:03 AM A relatively easy approach to handle multiple inputs, and particularly a mix of colored and uncolored inputs, in setting like one used in this script is:
This script already has a recursive traversal function (called rec), with some modifications it can be used to identify 'potentially colored transactions'. Moreover, if it produces such list via "reverse postordering", list will be dependency-sorted, see here: http://en.wikipedia.org/wiki/Depth-first_search#Vertex_orderings ("Reverse postordering produces a topological sorting of any directed acyclic graph.") Then for each transaction, we can count sum of values of colored inputs and use it color an appropriate number of outputs. Additional check should be made to make sure that all colored inputs go before all uncolored. However, there is a problem: a list of potentially colored transactions might be huge. Especially if you include uncolored outputs. To solve this performance problem one might limit depth of DFS by block number: i.e. do this coloring process in batches, block by block or something like that. Whenever you see a transaction in a block too far ahead, simple ignore it, it will be considered later. This works because transactions in later blocks cannot affect transactions in earlier blocks. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: matthewh3 on October 13, 2012, 07:13:23 PM As long as the shareholders don't massively disagree I'm going to offer out a 0.5% ownership of the former GLBSE mining stock/asset RSM - (https://bitcointalk.org/index.php?topic=63257.0) - That works out currently as ownership of 0.9(GH/s) of BFL-SC-Singles although we will be saving 50% of profits towards buying more ASIC's to increase the (MH/s) per share ratio. For you to implement this idea and maintain it. You wont receive the coloured coins relating to that 0.5% that will be held in a separate account managed by me but you will receive all profits made from 0.5% ownership as long as you maintain the code. I've also offered this bounty to this coloured coins project too - (https://bitcointalk.org/index.php?topic=106373.0) - so the first/best implementation will win the bounty. We don't need to use the coloured coins for about another month yet when we receive our first BFL-SC-Single.
Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: matthewh3 on October 13, 2012, 11:57:23 PM Is there anyway this idea could be used to hold motions/voting weighted off coloured coins ownership?
Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: killerstorm on October 14, 2012, 12:04:20 AM Is there anyway this idea could be used to hold motions/voting weighted off coloured coins ownership? Yes. Owners of colored coins can sign messages with private keys corresponding to addresses which hold colored coins. issuer, or perhaps some third party, would then collect these messages and check that they indeed come from owners of coins, i.e. shareholders. People might post these signed messages on forum to make voting public. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: jgarzik on October 14, 2012, 12:13:26 AM Is there anyway this idea could be used to hold motions/voting weighted off coloured coins ownership? Yes. The issuer may determine what public key currently controls a colored coin. That is the only information present in the public blockchain data. It is obvious that voting is possible: a colored coin holder may use the 'signmessage' feature to sign any arbitrary text using their bitcoin ECDSA keys. Let us assume that a colored coin has been sent to bitcoin address 1ABCD1234ABCD1234. 1. A public notice of voting is posted <somewhere>, of a vote. This notice includes a sample ballot, a simple text message format. 2. The owner of 1ABCD1234ABCD1234 downloads the sample ballot, edits it to reflect their vote, and then uses the 'signmessage' RPC to add a cryptographic signature. 3. The owner of 1ABCD1234ABCD1234 emails the signed ballot to voting@mycompany.com, or maybe, voting@thirdpartyballotservice.com. 4. The bond issuer, or 3rd party vote tabulation service, looks at the blockchain to verify that the email just received is signed by the holder of public key 1ABCD1234ABCD1234, and that 1ABCD1234ABCD1234 does indeed still control the colored coin. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: matthewh3 on October 14, 2012, 12:40:51 AM Is there anyway this idea could be used to hold motions/voting weighted off coloured coins ownership? Yes. The issuer may determine what public key currently controls a colored coin. That is the only information present in the public blockchain data. It is obvious that voting is possible: a colored coin holder may use the 'signmessage' feature to sign any arbitrary text using their bitcoin ECDSA keys. Let us assume that a colored coin has been sent to bitcoin address 1ABCD1234ABCD1234. 1. A public notice of voting is posted <somewhere>, of a vote. This notice includes a sample ballot, a simple text message format. 2. The owner of 1ABCD1234ABCD1234 downloads the sample ballot, edits it to reflect their vote, and then uses the 'signmessage' RPC to add a cryptographic signature. 3. The owner of 1ABCD1234ABCD1234 emails the signed ballot to voting@mycompany.com, or maybe, voting@thirdpartyballotservice.com. 4. The bond issuer, or 3rd party vote tabulation service, looks at the blockchain to verify that the email just received is signed by the holder of public key 1ABCD1234ABCD1234, and that 1ABCD1234ABCD1234 does indeed still control the colored coin. Cool, sounds complex but I'm sure it could be built into the new altered wallet and made simple enough. Another question while I'm still trying to grasp the concept. The initial creation of the coloured coins is stored in the blockchain of the wallet that created them. Is it very important the record of this genesis creation/transaction of the coloured coin is kept? If so how does this individual colour marked blockchain be distributed? Or does each wallet just keep its own new colour marked blockchain from receipt of the coloured coins to prove ownership? Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: jgarzik on October 14, 2012, 01:43:38 AM Another question while I'm still trying to grasp the concept. The initial creation of the coloured coins is stored in the blockchain of the wallet that created them. Is it very important the record of this genesis creation/transaction of the coloured coin is kept? If so how does this individual colour marked blockchain be distributed? Or does each wallet just keep its own new colour marked blockchain from receipt of the coloured coins to prove ownership? There is only one blockchain, the public blockchain. Let me try to draw an analogy: Every US dollar has a serial number on it. The US dollar version of colored coins would be analogous to: "the holder of $20 bill with serial number ABCD1234 owns Chevrolet Corvette VIN 137YA9031WE239523" Colored coins says "bitcoin ABCD1234", whatever its value, is somehow more special than regular bitcoins. This requires special software for the bond issuer and the bond holder, both, that recognizes bitcoin ABCD1234 as special. This is simply an agreement enforced (or not) by running special software. The bond issuer runs software that searches for the current public key holding ABCD1234, and pays dividends to that public key. The bond issuer does not know or care who is the owner. The bond holder runs software that stores ABCD1234 in a special wallet, separate from other bitcoin wallets. This guarantees that the bond holder does not accidentally spend their "special" coin accidentally -- analogous to accidentally giving a rare coin to a vending machine for soda. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: matthewh3 on October 14, 2012, 02:24:52 AM Another question while I'm still trying to grasp the concept. The initial creation of the coloured coins is stored in the blockchain of the wallet that created them. Is it very important the record of this genesis creation/transaction of the coloured coin is kept? If so how does this individual colour marked blockchain be distributed? Or does each wallet just keep its own new colour marked blockchain from receipt of the coloured coins to prove ownership? There is only one blockchain, the public blockchain. Let me try to draw an analogy: Every US dollar has a serial number on it. The US dollar version of colored coins would be analogous to: "the holder of $20 bill with serial number ABCD1234 owns Chevrolet Corvette VIN 137YA9031WE239523" Colored coins says "bitcoin ABCD1234", whatever its value, is somehow more special than regular bitcoins. This requires special software for the bond issuer and the bond holder, both, that recognizes bitcoin ABCD1234 as special. This is simply an agreement enforced (or not) by running special software. The bond issuer runs software that searches for the current public key holding ABCD1234, and pays dividends to that public key. The bond issuer does not know or care who is the owner. The bond holder runs software that stores ABCD1234 in a special wallet, separate from other bitcoin wallets. This guarantees that the bond holder does not accidentally spend their "special" coin accidentally -- analogous to accidentally giving a rare coin to a vending machine for soda. As I'm looking at issuing coloured coins based on the ownership of over $4,000 of ASIC's how do I prove ownership of the issued coloured coins permanently taking into account of hardware failures. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: jgarzik on October 14, 2012, 04:19:41 AM As I'm looking at issuing coloured coins based on the ownership of over $4,000 of ASIC's how do I prove ownership of the issued coloured coins permanently taking into account of hardware failures. The most important concept to remember is that colored coins are like rules of the road: they only work because everybody agrees on what side of the road to drive. There is no law of physics preventing cars from driving in the opposing lane of traffic. There is no software rule preventing you from using your colored coins to buy Alpaca socks at a web shop. The basic process works like this: 1. Publicly declare a list of coins in the existing blockchain as colored. 2. Transfer the colored coins to their new owners. These new owners may freely transfer them to other owners. 3. If the colored coin transfer follows the Colored Coin Rules(tm), software may search the blockchain, and precisely identify the list of colored coin holders. 4. If the colored coin transfer does not follow the Colored Coin Rules(tm), then that person is essentially "burning the money", by making it impossible to track the colored coin beyond a certain point. It is up to each colored coin owner to keep track of their own public keys. All other information is stored in the public blockchain. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: jl2012 on October 14, 2012, 04:44:49 AM As I'm looking at issuing coloured coins based on the ownership of over $4,000 of ASIC's how do I prove ownership of the issued coloured coins permanently taking into account of hardware failures. The most important concept to remember is that colored coins are like rules of the road: they only work because everybody agrees on what side of the road to drive. There is no law of physics preventing cars from driving in the opposing lane of traffic. There is no software rule preventing you from using your colored coins to buy Alpaca socks at a web shop. The basic process works like this: 1. Publicly declare a list of coins in the existing blockchain as colored. 2. Transfer the colored coins to their new owners. These new owners may freely transfer them to other owners. 3. If the colored coin transfer follows the Colored Coin Rules(tm), software may search the blockchain, and precisely identify the list of colored coin holders. 4. If the colored coin transfer does not follow the Colored Coin Rules(tm), then that person is essentially "burning the money", by making it impossible to track the colored coin beyond a certain point. It is up to each colored coin owner to keep track of their own public keys. All other information is stored in the public blockchain. I think a better version of rule 4 should be: If the colored coin transfer does not follow the Colored Coin Rules(tm), the last owner retains the extra value of the colored coin. (i.e. the last owner will still receive dividend etc.) However, that person may no longer transfer the extra value to other owners. The issuer may re-issue a new colored coin to the last owner to replace the burnt one, with or without service fee charged. This will prevent most "money burning accident". Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: bitfair on October 15, 2012, 01:29:47 PM Update
A new version of the script has been posted, and OP has been updated with a usage example that showcases the current capabilities of the program. The main new feature is the possibility to pay dividends from your wallet to the holders of colored coins. Enjoy! Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: bitfair on October 15, 2012, 01:49:42 PM I'd like to thank the big brains for weighing in here in this thread.
With the script now working "as I originally had in mind", I am now very keen on making improving the script and making it compatible with the approaches discussed by the venerable mr. killerstorm and sir jgarzik. However, there are so many long threads at this point that I don't have time to dig through the coal to find the diamonds, so if anyone can point to a whitepaper, a spec, a particularly enlightening post, preferably showing examples of transactions and how the color should be interpreted in the input/output for various approaches, then I would be very grateful. A deconstructed example of for instance 2 colored+2 uncolored inputs should be pretty comprehensive - anyone seen such a thing? But first, I would like to invite matthewh3 - as the only "asset issuer" that has weighed in so far - to describe a little more in detail what features he is looking for. Update: I've been reading up on the discussion ,and it seems that the consensus is something like this: https://bitcointalk.org/index.php?topic=106449.msg1203918#msg1203918 (https://bitcointalk.org/index.php?topic=106449.msg1203918#msg1203918), so I intend to try following those rules (until problems start surfacing). Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: jgarzik on October 15, 2012, 02:04:44 PM PS. Thank you for using 'sendmany' It helps keep blockchain bloat to a minimum.
Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: allten on October 15, 2012, 03:08:49 PM There's a bounty available:
https://bitcointalk.org/index.php?topic=106373.msg1269388#msg1269388 I'm hoping the main group of people pushing for the development of this technology will post a link to this bounty to inspire others to donate as well. This is really great stuff and I'm very excited to see where it will go. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: matthewh3 on October 15, 2012, 03:21:00 PM It'd be good if the coloured coins could be held in one blockchain.info wallet and dividends paid to any of the coins owners choosing. Also what keep's the proof of the coloured coins? If it's just your 'short python script' on my machine then I need a way to back proof up online and to be able to distribute it to each coloured coin owner. Sorry if that sounds stupid and/or I've missed the point, still trying to figure this all out.
Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: matthewh3 on October 15, 2012, 03:31:24 PM There's a bounty available: https://bitcointalk.org/index.php?topic=106373.msg1269388#msg1269388 I'm hoping the main group of people pushing for the development of this technology will post a link to this bounty to inspire others to donate as well. This is really great stuff and I'm very excited to see where it will go. I've also put a bounty up in this thread and the other thread - https://bitcointalk.org/index.php?topic=117630.msg1270041#msg1270041 Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: jgarzik on October 15, 2012, 03:57:30 PM It'd be good if the coloured coins could be held in one blockchain.info wallet and dividends paid to any of the coins owners choosing. Also what keep's the proof of the coloured coins? If it's just your 'short python script' on my machine then I need a way to back proof up online and to be able to distribute it to each coloured coin owner. Sorry if that sounds stupid and/or I've missed the point, still trying to figure this all out. Given current bitcoin software, it is strongly advisable to keep separate wallets for smartcoins (colored coins) and regular bitcoins. Mix the two at your peril; it is too easy to "spend away" an asset as regular bitcoins, with a single wallet. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: matthewh3 on October 15, 2012, 04:31:35 PM It'd be good if the coloured coins could be held in one blockchain.info wallet and dividends paid to any of the coins owners choosing. Also what keep's the proof of the coloured coins? If it's just your 'short python script' on my machine then I need a way to back proof up online and to be able to distribute it to each coloured coin owner. Sorry if that sounds stupid and/or I've missed the point, still trying to figure this all out. Given current bitcoin software, it is strongly advisable to keep separate wallets for smartcoins (colored coins) and regular bitcoins. Mix the two at your peril; it is too easy to "spend away" an asset as regular bitcoins, with a single wallet. Yes that was my idea to recommend use of a separate blockchain.info/wallet to asset holders as they do automatic backups to your email, Google drive or dropbox. I understand other online wallets can't be used as they mix your coins. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: Energizer on October 15, 2012, 05:29:36 PM Is it possible to force a specific transaction fee to any colored coin transaction?
For example: a transaction fee of 0.00050321 In this case the colored coin application/script should:
This way the application can guard colored coins from accidentally being spent. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: bitfair on October 15, 2012, 06:03:21 PM It'd be good if the coloured coins could be held in one blockchain.info wallet and dividends paid to any of the coins owners choosing. Also what keep's the proof of the coloured coins? If it's just your 'short python script' on my machine then I need a way to back proof up online and to be able to distribute it to each coloured coin owner. Sorry if that sounds stupid and/or I've missed the point, still trying to figure this all out. You prove that you own colored coins by holding the private key of the address they held at (same way as you prove that you own any bitcoin, in fact). For my script, the private keys of the addresses you generate with the client for holding colored coins are held in a configuration file. The file is relatively small and in plaintext, and can easily be backed up, sent by e-mail, stored offsite, etc. Better to show by example, perhaps: -------- 1. An "asset issuer" essentially says something like: "I will use the output number 2 from transaction 630bccacd6f4401fde53822af3f011daa47ec1bedd1702bf7d0be4391948f49b to represent 100% of the shares in my company, whoever holds the descendants of this output holds a proportional share of the company." Output number 2 from that transaction belongs to 1AEn3U5MhedXYRbpxLKmkL4r5Kz1XkdZA, as can be seen by the whole world at http://blockchain.info/tx/630bccacd6f4401fde53822af3f011daa47ec1bedd1702bf7d0be4391948f49b (http://blockchain.info/tx/630bccacd6f4401fde53822af3f011daa47ec1bedd1702bf7d0be4391948f49b), and can also be verified in their own local blockchain. 2. The "asset issuer" can now transfer those bitcoins or portions of those bitcoins to other addresses. The transfer will be stored in the public ledger/blockchain - everyone can verify that output number 2 from transaction 630bcc... was assigned to three new addresses in transaction d8e8dc799be1b552f29f8cbd2df24a1fcb9c2a9f4a43c9b4444b9dc329bbd17d, http://blockchain.info/tx/d8e8dc799be1b552f29f8cbd2df24a1fcb9c2a9f4a43c9b4444b9dc329bbd17d (http://blockchain.info/tx/d8e8dc799be1b552f29f8cbd2df24a1fcb9c2a9f4a43c9b4444b9dc329bbd17d). 60% of the value was transferred to 1KbDEaZ99YJYaT62emhFwabFoqQ6LYdJg9, 30% to 1DAHyXPNJjqLGFNqHhavrukWZ6XkY8Kj21 and 10% to 1Mhx4LMjbmN6KJ9B5BkdZ5zVWQP64F5TJC. The holders of these three addresses are now the new owners of the company, since they hold coins that descend from the "ancestor" transaction output. The evidence is in the public ledger for all to see. 3. The holders of these three addresses can again make transfers to other addresses, each time the public ledger/bitcoin blockchain will hold a record of the transaction, such that the genealogy can be traced back to the original ancestor that represented 100% of the company. -------- The script I have written essentially just makes sure that the transactions are "nicely" formed, in such a way that descendants of the ancestor are recorded in a very obvious manner in the bitcoin blockchain, and contains a mechanism to track the descendants. Did that make it clearer, or just mix it up even more (if so, sorry about that!)? Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: bitfair on October 15, 2012, 06:15:50 PM Is it possible to force a specific transaction fee to any colored coin transaction? For example: a transaction fee of 0.00050321 In this case the colored coin application/script should:
This way the application can guard colored coins from accidentally being spent. That might solve the problem if you could agree all client developers (Satoshi+MultiBit+Armory+Electrum+++) to agree that transactions with a fee of that specific value are pariah, which might be hard. Until then, I found it easier to simply store the keys for the addresses that hold colored coin separately from the normal wallet.dat. Cumbersome and ugly, some may argue, but I feel it certainly mitigates the problem. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: matthewh3 on October 15, 2012, 06:20:42 PM It'd be good if the coloured coins could be held in one blockchain.info wallet and dividends paid to any of the coins owners choosing. Also what keep's the proof of the coloured coins? If it's just your 'short python script' on my machine then I need a way to back proof up online and to be able to distribute it to each coloured coin owner. Sorry if that sounds stupid and/or I've missed the point, still trying to figure this all out. You prove that you own colored coins by holding the private key of the address they held at (same way as you prove that you own any bitcoin, in fact). For my script, the private keys of the addresses you generate with the client for holding colored coins are held in a configuration file. The file is relatively small and in plaintext, and can easily be backed up, sent by e-mail, stored offsite, etc. Better to show by example, perhaps: -------- 1. An "asset issuer" essentially says something like: "I will use the output number 2 from transaction 630bccacd6f4401fde53822af3f011daa47ec1bedd1702bf7d0be4391948f49b to represent 100% of the shares in my company, whoever holds the descendants of this output holds a proportional share of the company." Output number 2 from that transaction belongs to 1AEn3U5MhedXYRbpxLKmkL4r5Kz1XkdZA, as can be seen by the whole world at http://blockchain.info/tx/630bccacd6f4401fde53822af3f011daa47ec1bedd1702bf7d0be4391948f49b (http://blockchain.info/tx/630bccacd6f4401fde53822af3f011daa47ec1bedd1702bf7d0be4391948f49b), and can also be verified in their own local blockchain. 2. The "asset issuer" can now transfer those bitcoins or portions of those bitcoins to other addresses. The transfer will be stored in the public ledger/blockchain - everyone can verify that output number 2 from transaction 630bcc... was assigned to three new addresses in transaction d8e8dc799be1b552f29f8cbd2df24a1fcb9c2a9f4a43c9b4444b9dc329bbd17d, http://blockchain.info/tx/d8e8dc799be1b552f29f8cbd2df24a1fcb9c2a9f4a43c9b4444b9dc329bbd17d (http://blockchain.info/tx/d8e8dc799be1b552f29f8cbd2df24a1fcb9c2a9f4a43c9b4444b9dc329bbd17d). 60% of the value was transferred to 1KbDEaZ99YJYaT62emhFwabFoqQ6LYdJg9, 30% to 1DAHyXPNJjqLGFNqHhavrukWZ6XkY8Kj21 and 10% to 1Mhx4LMjbmN6KJ9B5BkdZ5zVWQP64F5TJC. The holders of these three addresses are now the new owners of the company, since they hold coins that descend from the "ancestor" transaction output. The evidence is in the public ledger for all to see. 3. The holders of these three addresses can again make transfers to other addresses, each time the public ledger/bitcoin blockchain will hold a record of the transaction, such that the genealogy can be traced back to the original ancestor that represented 100% of the company. -------- The script I have written essentially just makes sure that the transactions are "nicely" formed, in such a way that descendants of the ancestor are recorded in a very obvious manner in the bitcoin blockchain, and contains a mechanism to track the descendants. Did that make it clearer, or just mix it up even more (if so, sorry about that!)? Yeah it shed a bit of light. So do you recomend every shareholder I send the coloured coin first uses your new client to receive there coloured coins before sending them elsewhere for safe keeping. So they can get a copy of the ledger in the blockchain. I know I can just state - 630bccacd6f4401fde53822af3f011daa47ec1bedd1702bf7d0be4391948f49b - is the genesis coloured coin but I imagine its your client that makes visible these coins are coloured. Otherwise how do people trace there coloured coins back to - 630bccacd6f4401fde53822af3f011daa47ec1bedd1702bf7d0be4391948f49b - So in short people just need to save just tx - 630bccacd6f4401fde53822af3f011daa47ec1bedd1702bf7d0be4391948f49b - and their private-key to prove ownership. I suspect your new client does all the blockchain checking from tx - 630bccacd6f4401fde53822af3f011daa47ec1bedd1702bf7d0be4391948f49b ?? Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: Energizer on October 15, 2012, 06:22:43 PM Is it possible to force a specific transaction fee to any colored coin transaction? For example: a transaction fee of 0.00050321 In this case the colored coin application/script should:
This way the application can guard colored coins from accidentally being spent. That might solve the problem if you could agree all client developers (Satoshi+MultiBit+Armory+Electrum+++) to agree that transactions with a fee of that specific value are pariah, which might be hard. Until then, I found it easier to simply store the keys for the addresses that hold colored coin separately from the normal wallet.dat. Cumbersome and ugly, some may argue, but I feel it certainly mitigates the problem. I just think about it as a second layer of securing the colored coins. Actually I came to this point not only to guard colored coins but to make use of the transaction fee value as a messaging protocol command. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: Energizer on October 15, 2012, 06:44:02 PM As far as I understand your design doesn't have a mechanism for exchanging "shares/colored coins <-> BTC". I am still new to the term "colored coins", I came across it when I was trying to find any decentralized solution for exchanging Assets <-> BTC. Your design seems idle for issuing/tracking colored coins ownership. I am thinking to start using your implementation soon for my asset "Bitnodes". Please correct me if am wrong; there is one problem/feature that is missing in all colored coins implementations that I've researched, which is "a mechanism for exchange". I wouldn't argue that such exchange mechanism is beyond the concept of colored coins. What I mean by an exchange mechanism, is to have a mechanism to create ask/bid orders, and to be able to perform the exchange automatically in a decentralized manner by only relaying on the block chain and the colored coins software.
Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: bitfair on October 15, 2012, 06:53:42 PM Yeah it shed a bit of light. So do you recomend every shareholder I send the coloured coin first uses your new client to receive there coloured coins before sending them elsewhere for safe keeping. So they can get a copy of the ledger in the blockchain. I know I can just state - 630bccacd6f4401fde53822af3f011daa47ec1bedd1702bf7d0be4391948f49b - is the genesis coloured coin but I imagine its your client that makes visible these coins are coloured. Otherwise how do people trace there coloured coins back to - 630bccacd6f4401fde53822af3f011daa47ec1bedd1702bf7d0be4391948f49b - So in short people just need to save just tx - 630bccacd6f4401fde53822af3f011daa47ec1bedd1702bf7d0be4391948f49b - and their private-key to prove ownership. I suspect your new client does all the blockchain checking from tx - 630bccacd6f4401fde53822af3f011daa47ec1bedd1702bf7d0be4391948f49b ?? Correct: what your shareholders need to know is that 630bcca... is the ancestor/root/genesis, and after that the script figures out all the shareholders by traversing the list of "well-formed" transactions from there onwards. IF someone was adventurous enough (i.e. moreso than Indiana Jones or Ranulph Fiennes) to want to use this script at the moment, then I would recommend every shareholder to generate an "asset holding" address with this script. Thereafter, the asset issuer would make transfers to that address. Every shareholder would also have to be told the transaction ID of the genesis transaction (and the output number), which each one would then have to add to their client. Those concerned about security could also write their private key down on a piece of paper (it is stored in plaintext in the configuration file) and remove it from the configuration file. However, when making transfers, they would have to re-enter the private key in the config file... Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: killerstorm on October 15, 2012, 06:55:37 PM there is one problem/feature that is missing in all colored coins implementations that I've researched, which is "a mechanism for exchange". I wouldn't argue that such exchange mechanism is beyond the concept of colored coins. What I mean by an exchange mechanism, is to have a mechanism to create ask/bid orders, and to be able to perform the exchange automatically in a decentralized manner by only relaying on the block chain and the colored coins software. I definitely plan to implement an exchange mechanism in client software I'm working on. However I think ask/bid orders should be broadcast on a separate network, doing it via blockchain would be kind of a waste of resources. (However it isn't totally out of questions, there are alt-chain designs which are more scalable than bitcoin and they will be able to handle bid/ask traffic in blockchain.) Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: killerstorm on October 15, 2012, 07:07:44 PM through the coal to find the diamonds, so if anyone can point to a whitepaper, a spec, a particularly enlightening post, preferably showing examples of transactions and how the color should be interpreted in the input/output for various approaches, then I would be very grateful. A deconstructed example of for instance 2 colored+2 uncolored inputs should be pretty comprehensive - anyone seen such a thing? This thread has links to everything: rules, examples, code, interactive demo: https://bitcointalk.org/index.php?topic=114571.0 However this version of code might be easier to read: https://github.com/killerstorm/colored-coin-tools/blob/master/color.js Only compute_colors() function is necessary, the rest is just validation/sanity check. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: Energizer on October 15, 2012, 07:12:01 PM there is one problem/feature that is missing in all colored coins implementations that I've researched, which is "a mechanism for exchange". I wouldn't argue that such exchange mechanism is beyond the concept of colored coins. What I mean by an exchange mechanism, is to have a mechanism to create ask/bid orders, and to be able to perform the exchange automatically in a decentralized manner by only relaying on the block chain and the colored coins software. I definitely plan to implement an exchange mechanism in client software I'm working on. However I think ask/bid orders should be broadcast on a separate network, doing it via blockchain would be kind of a waste of resources. (However it isn't totally out of questions, there are alt-chain designs which are more scalable than bitcoin and they will be able to handle bid/ask traffic in blockchain.) I am looking forward for your exchange mechanism solution. Where can I follow that? What do you think about using transaction fees values as messaging protocol events for a colored coins application? Do you know of any implementation that applies that? Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: bitfair on October 15, 2012, 07:21:21 PM As far as I understand your design doesn't have a mechanism for exchanging "shares/colored coins <-> BTC". I am still new to the term "colored coins", I came across it when I was trying to find any decentralized solution for exchanging Assets <-> BTC. Your design seems idle for issuing/tracking colored coins ownership. I am thinking to start using your implementation soon for my asset "Bitnodes". Please correct me if am wrong; there is one problem/feature that is missing in all colored coins implementations that I've researched, which is "a mechanism for exchange". I wouldn't argue that such exchange mechanism is beyond the concept of colored coins. What I mean by an exchange mechanism, is to have a mechanism to create ask/bid orders, and to be able to perform the exchange automatically in a decentralized manner by only relaying on the block chain and the colored coins software. Indeed, there is no built-in design for exchanging, the design simply does the easy part - issuing/tracking ownership of colored coins. (It can also pay dividends to the owners, but that is not really conceptually different.) The question of decentralized exchange is a somewhat separate (but related) issue. I had some thoughts on it while I was trying to sleep last night, I might try a simple prototype of that too when I'm relatively satisfied that this script does what I want it to. What I had in mind was not necessarily decentralized, but more of a protocol that would be agnostic to the transport layer. But imagine that you have a client and a server (in a p2p design, each node could be both). The protocol would be relatively simple: 1) CLIENT connects to SERVER 2) CLIENT requests order book from SERVER Then either: 3a) CLIENT wants to enter a new order in the book: e.g. BID: ASSET1@400BTC, and signs it with address(es) that controls at least 400BTC, sends to SERVER 4a) SERVER verifies signature, enters into order book 5a) SERVER broadcasts order to all CLIENTS or: 3b) CLIENT wants to hit an order from the book: constructs a transaction with the inputs taken from own wallet and inputs specified in the order, signs his inputs and sends to SERVER 4b) SERVER broadcasts to incomplete transaction to all CLIENTS 5b) The CLIENT that originally made the offer signs the last inputs, and broadcasts the complete transaction on the bitcoin network. All nodes will also need to monitor the blockchain, so that if any of the inputs are spent that are part of an unfilled order, that order is immediately removed from the books. There's not really that much needed to make it work. I'm sure a lot of people have had the same (probably much more clever) idea(s). Decentralized or centralized, following such a protocol would at least not leave you with a single point of failure - asset ownership would be public and undisputable at all times, the blockchain would contain a complete price history, and you essentially wouldn't have to trust any third party. The worst thing that could happen is that the counterparty does not sign the transaction when you want to hit an order from the book, but in that case you keep your BTC anyway. Anyway - sorry, offtopic ;) PS: Making the transaction fees "information-bearing" doesn't sound very good to me. Imagine if you can afford the transaction, but you can't afford to make the transaction with the message you want? Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: bitfair on October 15, 2012, 07:25:04 PM through the coal to find the diamonds, so if anyone can point to a whitepaper, a spec, a particularly enlightening post, preferably showing examples of transactions and how the color should be interpreted in the input/output for various approaches, then I would be very grateful. A deconstructed example of for instance 2 colored+2 uncolored inputs should be pretty comprehensive - anyone seen such a thing? This thread has links to everything: rules, examples, code, interactive demo: https://bitcointalk.org/index.php?topic=114571.0 However this version of code might be easier to read: https://github.com/killerstorm/colored-coin-tools/blob/master/color.js Only compute_colors() function is necessary, the rest is just validation/sanity check. Thanks, I'll certainly take a close look at this! The order-based method of coloring certainly makes a lot of sense. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: Energizer on October 15, 2012, 08:22:47 PM PS: Making the transaction fees "information-bearing" doesn't sound very good to me. Imagine if you can afford the transaction, but you can't afford to make the transaction with the message you want? What do you mean by "affording a transaction but can't afford the transaction message you want" can you give an example? If you just make use of the last 2 digits in the transaction fee: 0.000000## this can give 100 different variation = 100 different events/messages I don't think that you would need more than 100 different messages, knowing that currently your design is based on a single message: colored coins moving from one address to another. Imagine if you can have 100 different events/messages going in/out of a BTC address. In this case you wouldn't even need to move the colored coins! the colored coin term wouldn't even apply here. Cause by then you would be applying a virtual messaging protocol on top of the block chain, where nodes = BTC addresses, messages/events = transaction fees, message/event payload = the value being transfered. Only then the variations that such design can give would allow a decentralized exchange mechanism to take place: You want to sell 10 shares @ 0.1? send a transaction to the BTC address you want to receive payment to with the value you want to accept per share and a transaction fee with last digits = to the "ask order" message/event. The same senario can be used in buying the shares. Does that make any sense? Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: Energizer on October 15, 2012, 09:58:16 PM What would be more interesting is instead of sending the message in the transaction fee, is to send the message as a small BTC amount to the issuer's BTC address as a second recipient in sendmany(). This way all messages related to that particular asset can be tracked through the issuer's BTC address. The issuer can then benefit from the messaging mechanism instead of wasting BTC in the transaction fee.
Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: yoniassia on October 15, 2012, 11:36:30 PM As far as I understand your design doesn't have a mechanism for exchanging "shares/colored coins <-> BTC". I am still new to the term "colored coins", I came across it when I was trying to find any decentralized solution for exchanging Assets <-> BTC. Your design seems idle for issuing/tracking colored coins ownership. I am thinking to start using your implementation soon for my asset "Bitnodes". Please correct me if am wrong; there is one problem/feature that is missing in all colored coins implementations that I've researched, which is "a mechanism for exchange". I wouldn't argue that such exchange mechanism is beyond the concept of colored coins. What I mean by an exchange mechanism, is to have a mechanism to create ask/bid orders, and to be able to perform the exchange automatically in a decentralized manner by only relaying on the block chain and the colored coins software. Once a there is an ability to color coins, there is a built in mechanism of exchanging any colored BTC to any colored BTC (regular BTC can simply considered white BTC). For example, lets assume I start a color called BTX , coloring is simply accepting some initial genesis input as those colored coins, I can now exchange with you 1 BTX for 2 BTC, we need to trust each other and agree on a price offcourse, there are mechanism in bitcoin to act as escrow for this transaction, but those are 3rd parties. So at anytime you can look at the blockchain and see all BTX/BTC transactions, since colors are public, and you can show last price and historical prices, you can simply agree on the last price, or last price + x. When you mentioned bid/ask, that is simply a matching engine, that might require another 3rd party, but is not necessary for the basic use of an exchange, as a bid/ask book is actually centralized for of exchange. Take for example currency trading, there is no ask/bid centralized anywhere, yet it is the most sophisticated and liquid market in the world, possibly because of its OTC and decentralized model. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: Energizer on October 15, 2012, 11:51:09 PM As far as I understand your design doesn't have a mechanism for exchanging "shares/colored coins <-> BTC". I am still new to the term "colored coins", I came across it when I was trying to find any decentralized solution for exchanging Assets <-> BTC. Your design seems idle for issuing/tracking colored coins ownership. I am thinking to start using your implementation soon for my asset "Bitnodes". Please correct me if am wrong; there is one problem/feature that is missing in all colored coins implementations that I've researched, which is "a mechanism for exchange". I wouldn't argue that such exchange mechanism is beyond the concept of colored coins. What I mean by an exchange mechanism, is to have a mechanism to create ask/bid orders, and to be able to perform the exchange automatically in a decentralized manner by only relaying on the block chain and the colored coins software. Once a there is an ability to color coins, there is a built in mechanism of exchanging any colored BTC to any colored BTC (regular BTC can simply considered white BTC). For example, lets assume I start a color called BTX , coloring is simply accepting some initial genesis input as those colored coins, I can now exchange with you 1 BTX for 2 BTC, we need to trust each other and agree on a price offcourse, there are mechanism in bitcoin to act as escrow for this transaction, but those are 3rd parties. So at anytime you can look at the blockchain and see all BTX/BTC transactions, since colors are public, and you can show last price and historical prices, you can simply agree on the last price, or last price + x. When you mentioned bid/ask, that is simply a matching engine, that might require another 3rd party, but is not necessary for the basic use of an exchange, as a bid/ask book is actually centralized for of exchange. Take for example currency trading, there is no ask/bid centralized anywhere, yet it is the most sophisticated and liquid market in the world, possibly because of its OTC and decentralized model. The method of exchange you've explained is the only possible way in the current design and that is exactly what I am trying to stay away from. We still need a decentralized exchange mechanism, why?
Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: yoniassia on October 16, 2012, 12:23:29 AM There's a bounty available: https://bitcointalk.org/index.php?topic=106373.msg1269388#msg1269388 I'm hoping the main group of people pushing for the development of this technology will post a link to this bounty to inspire others to donate as well. This is really great stuff and I'm very excited to see where it will go. Taking your 2, and adding another 20 BTC donation and adding link to a public document that started the documentation : https://docs.google.com/document/d/1AnkP_cVZTCMLIzw4DvsW6M8Q2JC0lIzrTLuoWu2z1BE/edit (https://docs.google.com/document/d/1AnkP_cVZTCMLIzw4DvsW6M8Q2JC0lIzrTLuoWu2z1BE/edit) Anyone who wants editing rights, simply send me your email in a private message Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: bitfair on October 16, 2012, 06:08:03 PM through the coal to find the diamonds, so if anyone can point to a whitepaper, a spec, a particularly enlightening post, preferably showing examples of transactions and how the color should be interpreted in the input/output for various approaches, then I would be very grateful. A deconstructed example of for instance 2 colored+2 uncolored inputs should be pretty comprehensive - anyone seen such a thing? This thread has links to everything: rules, examples, code, interactive demo: https://bitcointalk.org/index.php?topic=114571.0 However this version of code might be easier to read: https://github.com/killerstorm/colored-coin-tools/blob/master/color.js Only compute_colors() function is necessary, the rest is just validation/sanity check. killerstorm, I imagine you could be watching, so let me ask a question about an aspect your algorithm/code/example in color.js that I am having some difficulty with regarding transactions with several inputs of the same color: during "traversing the tree of ownership" to determine owners of the colored coins, at some point you may see a transaction where two inputs have the same color, but you are only aware that one of the inputs are colored (while following the input that lead first lead you to hit the node). During a traversal, how can you be sure that you have the (same-)color information for all the inputs? I was thinking "well, just process in order of appearance", but if the transaction with two inputs of the same color occurs in the same block as the transaction that adds color to one of the inputs, we again have a problem. Any ideas? PS: It would be fun if you have any test-cases that are available in the blockchain that could be checked, to verify that our interpretations on how color is transferred from inputs to outputs coincide... Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: killerstorm on October 16, 2012, 07:55:36 PM I imagine you could be watching, so let me ask a question about an aspect your algorithm/code/example in color.js that I am having some difficulty with regarding transactions with several inputs of the same color: during "traversing the tree of ownership" to determine owners of the colored coins, at some point you may see a transaction where two inputs have the same color, but you are only aware that one of the inputs are colored (while following the input that lead first lead you to hit the node). Well, yes, that's a problem. Here's one of possible solutions outlined: https://bitcointalk.org/index.php?topic=117630.msg1269200#msg1269200 Quote During a traversal, how can you be sure that you have the (same-)color information for all the inputs? You shouldn't color them when you're traversing, instead you can collect topo-sorted list and them color them one by one. Quote PS: It would be fun if you have any test-cases that are available in the blockchain that could be checked, to verify that our interpretations on how color is transferred from inputs to outputs coincide... Yep that would be cool, but I don't have any non-trivial examples in blockchain. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: matthewh3 on October 18, 2012, 07:17:44 AM There's a bounty available: https://bitcointalk.org/index.php?topic=106373.msg1269388#msg1269388 I'm hoping the main group of people pushing for the development of this technology will post a link to this bounty to inspire others to donate as well. This is really great stuff and I'm very excited to see where it will go. Taking your 2, and adding another 20 BTC donation and adding link to a public document that started the documentation : https://docs.google.com/document/d/1AnkP_cVZTCMLIzw4DvsW6M8Q2JC0lIzrTLuoWu2z1BE/edit (https://docs.google.com/document/d/1AnkP_cVZTCMLIzw4DvsW6M8Q2JC0lIzrTLuoWu2z1BE/edit) Anyone who wants editing rights, simply send me your email in a private message Maybe one of you should start a bounty wallet on this site - https://booster.io/ - so its easier for other people to add small bits too. Edit: Please be cautious when using it, but feel free to criticise, modify and contribute. And if you like it, support it: 1GsnaaAWYMb7yPwBQ19bSLLMTtsfSyjqg3. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: matthewh3 on October 18, 2012, 07:21:16 AM There are now many threads about "colored coins", "smart contracts" and otherwise tracking specific coins through the blockchain. I have created a simple command-line Python program to handle tracking of "colored coins", "smart contracts" or "blockchain securities" in the blockchain. There are other approaches, and the one I have taken is very simple, but it is a working solution (primitively duct-taped and glued together). I also have not read gone into the details of the other approaches, so it is probably safe to say that the method I have created is completely incompatible with the other methods (which are probably much smarter too). But it is a live and implemented solution, which gives it an advantage over others. It is short, easy to modify and fun to play with. It might be useful for some adventurous security issuers who are looking for a solution now that GLBSE is shutting down. Full source: http://pastebin.com/NnNug0nL (http://pastebin.com/NnNug0nL) Update Oct 15: The source code has been updated, the new version includes functions to pay dividends to holders of the colored coins. Also, it has been tested more thoroughly, and I have created a 12-step usage example that shows the current capabilities of the script. Usage example: Code:
Planned features: - GUI - Option to add transaction fee on asset transfers (it is very annoying when transactions never confirm) - Compatibility with the other approaches Please be cautious when using it, but feel free to criticise, modify and contribute. And if you like it, support it: 1GsnaaAWYMb7yPwBQ19bSLLMTtsfSyjqg3. Will your coloured coins work with this 'coloured coin stock market project' - https://bitcointalk.org/index.php?topic=118672.0 Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: bitfair on October 18, 2012, 01:13:53 PM Update
The source code has been updated in OP - the new version includes the functions to include a transaction fee from an (uncolored!) address in your standard/satoshi-client wallet when transferring assets so that the transaction is more likely to confirm more quickly (command-line option -w <fee>, where <fee> is the fee you want to pay in BTC, e.g. -w 0.005 for half a bitcent). Also, the tracking of colored coins is now also believed to be compatible with other approaches for "order-based" tracking, such as the one used in killerstorm's modified Satoshi client (however, I still want to build up a bunch of test-cases to see if the clients interpret all the cases in the same way). Next, I think it is time to create ample test-cases, and tidy up the code - it has turned into a bit of a spaghetti-ball. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: bitfair on October 18, 2012, 01:19:57 PM Will your coloured coins work with this 'coloured coin stock market project' - https://bitcointalk.org/index.php?topic=118672.0 According to my understanding of killerstorm's approach(es), there is no reason to believe that the approach in this script should be incompatible. But it is difficult to be sure until there are actual implementations (or detailed specs), so in the end the script might require modifications to be compatible. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: matthewh3 on November 08, 2012, 03:17:20 AM Can the dividends automatically be forwarded to a separate wallet address and if it had a list of dividend wallet address built in would you be able to edit it for when shares are sold. Also could your script work with Electrum or even possibly blockchain.info/wallet ??? Sorry if that sounds stupid ???
Edit: Having to download the full blockchain to verify your coloured coins will hinder its adoption. Many people are now using thin-clients rather than full blown desktop PC's now. Having an Electrum version or even a hack of blockchain.info/wallet would be good. Title: Re: Blockchain security tracking/colored coins/smart contracts - short python script Post by: jtimon on November 09, 2012, 10:03:26 AM Update The source code has been updated in OP - the new version includes the functions to include a transaction fee from an (uncolored!) address in your standard/satoshi-client wallet when transferring assets so that the transaction is more likely to confirm more quickly Great!! Does it support mutliple trades (Ripple)? For example... (A) 100 btc -> (B) 1 satoshiB -> (C) 1 satoshiC -> (D) or circular trades... (A) 100 btc -> (B) 1 satoshiB -> (C) 1 satoshiC -> (D) 1 satoshiD -> (A) That would be a decentralized Ripple implementation. |