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Title: If i wanted to find somone who was reciving bitcoins, how hard would it be? Post by: Rofer on October 23, 2011, 08:10:45 PM in other words how traceable are they?
Title: Re: If i wanted to find somone who was reciving bitcoins, how hard would it be? Post by: kiyote on October 23, 2011, 10:23:56 PM There are others out there who probably know better, but I'm under the impression that they could trace the transactions back through the block chain to the original sender. It all depends how careful you where with all your addresses. If you ever allow an address connected back to you, it can be connected back to you.
More is on the wiki: https://en.bitcoin.it/wiki/Anonymity Title: Re: If i wanted to find somone who was reciving bitcoins, how hard would it be? Post by: rplg on October 23, 2011, 11:51:53 PM I am not sure exactly how this is done but it is possible to find the IP of a node which made the transaction. If you are lucky enough to not end up with a Tor IP or anything like that, you might have found the IP of the person you are looking for.
Apart from that, when transferring coins you do not necessarily end up holding the same coins. An example is when using online wallets - the coins are withdraws from the online wallets, and not always the same address you sent the coins to. So if you do not manage to get the IP address easily, you would have to figure out which of the addresses in the blockchain belong to e.g. MtGox or any other online wallet service, then provide some legitimate reason for them to give you info of the user (which you probably will need a court order to do). If you are lucky, the user you are looking for bought them from an exchange which will easily hand out the info. If, however, the coins go through a couple of addresses before they get cashed out at an exchange, the user you end up catching has plausible deniability - what if those addresses the coins have gone through are not owned by this user? Again, you would need to prove that they hold all of the private keys for all the addresses. This is my take on it. Title: Re: If i wanted to find somone who was reciving bitcoins, how hard would it be? Post by: Causer Fons on October 24, 2011, 06:21:09 PM quite difficult unless you are willing to undertake some expensive investigations
however any remaining doubts about anonymity could perhaps only be remove if there were a proper BTC mixer service.. Title: Re: If i wanted to find somone who was reciving bitcoins, how hard would it be? Post by: RodeoX on October 25, 2011, 03:26:19 PM If you knew their receiving address you could search for it in blockexplorer. It would tell you how much has been sent to that address.
Title: Re: If i wanted to find somone who was reciving bitcoins, how hard would it be? Post by: Akemashite Omedetou on October 25, 2011, 03:37:46 PM Quote I am not sure exactly how this is done but it is possible to find the IP of a node which made the transaction. This is not 100% correct. While yes, it is certainly might somehow be possible to find the IP, practically this is very hard to do. Own transaction which a node sends out looks just the same to the other nodes as someone else's transaction. Bitcoin does not only redistribute it's own transactions, but all the transactions from the network that it has collected up to that point. So sure, if you have control over the majority of the network, and have somehow synchronised their clocks to milliseconds, then maybe, in certain cases you can possibly do a timing attack and guess which node was the first one sending a certain transaction. But in reality - No. Title: Re: If i wanted to find somone who was reciving bitcoins, how hard would it be? Post by: kiyote on October 25, 2011, 06:45:51 PM Quote I am not sure exactly how this is done but it is possible to find the IP of a node which made the transaction. This is not 100% correct. While yes, it is certainly might somehow be possible to find the IP, practically this is very hard to do. Own transaction which a node sends out looks just the same to the other nodes as someone else's transaction. Bitcoin does not only redistribute it's own transactions, but all the transactions from the network that it has collected up to that point. So sure, if you have control over the majority of the network, and have somehow synchronised their clocks to milliseconds, then maybe, in certain cases you can possibly do a timing attack and guess which node was the first one sending a certain transaction. But in reality - No. To paraphrase the example in the Anonymity page of the wiki, lets say that a user posts in the forum, as well as wants to remain anonymous. The user posts a bitcoin address in his signature, and because he's helpful, people send him the occasional coin. By watching his transactions, and their sizes (which are public), you can get a very good idea which other accounts are owned by our forum user. And since forums are easier to trace than bitcoin, you now have a strong connection between IPs, usernames, locations, etc to a bunch of bitcoin addresses. Changing your receive address every time you get accept a new transaction makes this harder, but people aren't always good with that, especially if you are using bitcoins to make purchases. Title: Re: If i wanted to find somone who was reciving bitcoins, how hard would it be? Post by: Akemashite Omedetou on October 26, 2011, 03:55:14 AM Quote I am not sure exactly how this is done but it is possible to find the IP of a node which made the transaction. This is not 100% correct. While yes, it is certainly might somehow be possible to find the IP, practically this is very hard to do. Own transaction which a node sends out looks just the same to the other nodes as someone else's transaction. Bitcoin does not only redistribute it's own transactions, but all the transactions from the network that it has collected up to that point. So sure, if you have control over the majority of the network, and have somehow synchronised their clocks to milliseconds, then maybe, in certain cases you can possibly do a timing attack and guess which node was the first one sending a certain transaction. But in reality - No. To paraphrase the example in the Anonymity page of the wiki, lets say that a user posts in the forum, as well as wants to remain anonymous. The user posts a bitcoin address in his signature, and because he's helpful, people send him the occasional coin. By watching his transactions, and their sizes (which are public), you can get a very good idea which other accounts are owned by our forum user. And since forums are easier to trace than bitcoin, you now have a strong connection between IPs, usernames, locations, etc to a bunch of bitcoin addresses. Changing your receive address every time you get accept a new transaction makes this harder, but people aren't always good with that, especially if you are using bitcoins to make purchases. Yep, of course, I thought that was implied if someone wants to stay anonymous. Also, if someone publically writes "my ip is this and my address it this", it also becomes very easy to find him/her :P Title: Re: If i wanted to find somone who was reciving bitcoins, how hard would it be? Post by: Red on October 26, 2011, 04:28:34 AM in other words how traceable are they? This is probably your best real world example of how it can be done. An Analysis of Anonymity in the Bitcoin System (http://arxiv.org/abs/1107.4524) I have some old posts (https://bitcointalk.org/index.php?topic=624.msg6618#msg6618) somewhere in these forums that could be considered a primer (https://bitcointalk.org/index.php?topic=596.msg6162#msg6162) to that paper. Title: Re: If i wanted to find somone who was reciving bitcoins, how hard would it be? Post by: kiyote on October 26, 2011, 01:39:34 PM Quote I am not sure exactly how this is done but it is possible to find the IP of a node which made the transaction. This is not 100% correct. While yes, it is certainly might somehow be possible to find the IP, practically this is very hard to do. Own transaction which a node sends out looks just the same to the other nodes as someone else's transaction. Bitcoin does not only redistribute it's own transactions, but all the transactions from the network that it has collected up to that point. So sure, if you have control over the majority of the network, and have somehow synchronised their clocks to milliseconds, then maybe, in certain cases you can possibly do a timing attack and guess which node was the first one sending a certain transaction. But in reality - No. To paraphrase the example in the Anonymity page of the wiki, lets say that a user posts in the forum, as well as wants to remain anonymous. The user posts a bitcoin address in his signature, and because he's helpful, people send him the occasional coin. By watching his transactions, and their sizes (which are public), you can get a very good idea which other accounts are owned by our forum user. And since forums are easier to trace than bitcoin, you now have a strong connection between IPs, usernames, locations, etc to a bunch of bitcoin addresses. Changing your receive address every time you get accept a new transaction makes this harder, but people aren't always good with that, especially if you are using bitcoins to make purchases. Yep, of course, I thought that was implied if someone wants to stay anonymous. Also, if someone publically writes "my ip is this and my address it this", it also becomes very easy to find him/her :P I don't mean someone types "my ip is this and this," I mean someone types "my bitcoin address is this and this." Boards tend to keep track of IPs anyway. I'm not sure if it's available to anyone but the administrator, but they usually do. Also, people tend to use the same/similar handles on a lot of different internet sites, so that's just more tracking data. |