Silk Road forums
Discussion => Security => Topic started by: jameslink2 on September 11, 2012, 02:43 am
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I have seen a lot of talk about bitcoins not being anonymous and how they can be traced and everyone should use a mixer, etc, etc, etc.
I have been looking at block chains for over a month and I can not find it. I know if they catch user A and have his bitcoin address they can then get him to say who he sent the coin to and link user B with an address, grab user B and repeat, on and on. However, this is the same for any communication It is simply tracing the chain of events.
I can not see, by looking at block chains or any other analysis, any way to track it back to SR or Bit Fog, or any other TOR site that uses bit coin.
Mind you, I can see where the bit coin was transferred between tor exit nodes. I assume that people are pointing their bitcoin client to the tor network. That in and of it self may be suggestive of a link to SR but the mixers in onion land do not fix that.
So, Is this tracing bitcoin a bit over blown or did I miss something?
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good question . . . I'd like to know this too.
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Wow, not a single response other than some one else that would like to know.
Well Metta, looks like we are both looking for an answer.
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Nice read, but again we have an analysis of the bitcoin flow with out the DE-anonymoizing of the thief who stole 25k bitcoin.
From the comments at the bottom of the article
We don't set out to to DE-anonymise the thief - we are researchers, not law enforcement, and we are just using that as an example to show its possible to trace the flow of Bitcoins around the network.
Following a flow and DE-anonymoising someone are two very different things. Seeing as the bitcoin client or daemon can have an unlimited number of address, and provided it is linked into the TOR network, those addresses are not directly linked to an IP then transactions done across the tor network are not something that can be DE-anonymised easily.
Add to that the simple fact that SR is a mixer/tumbler and that the coins paid in by user A are not the same coins that vendor B takes out of the system and there is a break right there in the chain.
I am still not convinced that you can de-anonymize a person based on a block chain analysis and coin movements with out putting in some MAJOR work to trace the identity via traditional detective work and a lot of luck.
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I am still not convinced that you can de-anonymize a person based on a block chain analysis and coin movements with out putting in some MAJOR work to trace the identity via traditional detective work and a lot of luck.
You are correct. While an analysis of the transaction chain can be made, determining the person behind any of the transactions would normally require other, more standard, methods of investigation. Of course mistakes are always made. If, for example, one were to post a Bitcoin address in their forum signature and then later send a transaction with multiple inputs that included that address, one could associate all the input addresses in that transaction with that forum user. Of course this would still require more traditional detective work to determine the forum user's identity.
Regardless, I retain a bit of healthy paranoia and always use various mixing services when I send funds in and out of SR.
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Regardless, I retain a bit of healthy paranoia and always use various mixing services when I send funds in and out of SR.
I am not saying that a little paranoia is not a healthy thing to have. I am saying that what people think and the truth may be too different things.
How about an example. The bitcoin daemon that is used by servers like SR to manage bitcoins assigns a new address every time it receives coins. This is automatic, so if you log into your SR account and deposit coins into SR then come back in an hour your bit coin address will be different. Send more coins the next day and they are to a new address.
Now, it is believed that SR simply maintains your coin count in a database. This would account for everything I have seen so far from the lack of the bitcoin transfer fees to the way it pays in and out. Thus when you pay a vendor the coins are transferred outside of the bitcoin network. When the vendor withdraws the coins it pays out of the main bitcoin daemon and it works on a first in first out (FIFO) principal. So the coins paid to the vendors external wallet are not the same coins you paid in but ones that SR has in holding.
The list of bitcoin addresses that SR has in use or has used are all internal to SR and no one person knows them all with the exception of DPR.
If every address is single use, then there is no way for a person to be linked to the address and no way to link all/a portion of/or any of the addresses to SR. If the vendors wallet is using the same basic system them every payment received is to a new address. Now if the vendor is using something like the auto-payout function then every payment is sent to the same address giving them a way to link the single address to all received payments. In this instance I can see how the use of a mixer could be helpful but if the mixer pays out to a single address and is on the onion network then there is no way to tell the difference between the mixer and SR when doing traffic analysis.
The point of this is that traffic analysis of the bitcoin network makes some pretty charts and graphs but is not a way to link payments from one person to another if they are using even the basic common sense.
By definition I take this to mean that there bitcoin client is attached to tor and every payout is to a unique address.
or a passive attacker could subpoena gox and all the other major exchanges and compel them to reveal if they own a certain address, and if they do what account it's associated with
True, however they could not subpoena every website that takes bitcoin and every one of them generates a new address for every payment received.
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I should note at this point I have not withdrawn my bitcoin from the bitcoin network. I have been creating servers with bitcoin daemons on them and doing tests, block chain analysis, bitcoin flow analysis, and diving into the way that bitcoin transfers and functions. I am attempting to gain a deeper understanding of the system that currently holds my money and how that money can be moved, transferred, exchanged, and withdrawn.
In doing so I am finding it harder and harder to justify the belief that one can be easily DE-anonymoized provided they take a few basic steps.
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ok, I guess I understand all this . . . a little. I am probably not being ultra safe by having bitinstant deposit directly to my SR account. If I was dealing in large amounts or was a vendor, I'd be more cautious about my activities, but I'm a little guy just trying to score some blow every so often.
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My personal findings, and you can take them as you see fit, is that bitinstant to an SR account is not a problem. Your bitcoin address for deposit changes after each transaction so there is no way to link it to SR.
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I am still not convinced that you can de-anonymize a person based on a block chain analysis and coin movements with out putting in some MAJOR work to trace the identity via traditional detective work and a lot of luck.
You need a point of reference if _Anyone_ can be identified in a transaction anywhere down or up the line. De-anonymization starts from there. The trick is not to leave any trace if at all possible or if there is any mix coins using appropriate measures to re-anonymize them as much as possible.
The whole "taint" aspect which blockchain.info measures is interesting. Depending on how taint is measured I think many/most coins will have some taint.
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My personal findings, and you can take them as you see fit, is that bitinstant to an SR account is not a problem. Your bitcoin address for deposit changes after each transaction so there is no way to link it to SR.
Hi James,
Thanks for your reassurance. :-)
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The real issue is what evidence a jury can be presented with that they might feel is compelling enough to believe in. Cover your virtual tracks AT HOME, before you worry about your bits and pieces.
Modzi