What sites exist to check if an address is involved in reported activity?

[rebuilder]

Unless you know of a method that would guarantee 100% accuracy and 100% reliability when connecting an identity and their actions with a specific Bitcoin transaction, a coin is a coin. No need to wish anything, it is so.

I have to, reluctantly, agree with znort. As long as coins can be tracked, whether foolproof or not, there are less and more desirable coins. Currently there's no readily available method to check coins for taint before receiving them, so the problem is somewhat academic. Maintaining a database of "illegitimate" coins is conceivable, though. It can be circumvented, and would be a bad idea in my opinion, but people tend to have ideas different from mine. Pooh-poohing won't protect anyone against the kind of hell such a taint database would unleash. Increasing Bitcoin anonymity would.

[hazek]

If you find any "less desirable" coins, please don't hesitate for a second sending them to me. I'll gladly spend them in your place.

[BlackBison]

ok I will buy any 1 btc regardless of its history for 0.9 of my own minty fresh btc.. any takers? 

[kjj]

ok I will buy any 1 btc regardless of its history for 0.9 of my own minty fresh btc.. any takers? 

Shit, I'll pay extra for coins from newsworthy events.  Premium negotiable depending on the event and the purity of the coins as I get them.

[BlackBison]

ok I will buy any 1 btc regardless of its history for 0.9 of my own minty fresh btc.. any takers? 

Thank you for proving my point: you just described the business of coin laundering ass-backward.

If coins were fungible, why would coin laundering service exist and get used ?

paranoia? 'just in case' from heavy silkroad sellers? if the y2k bug wasn't going to happen why did 'electronic preparation' services exist and get used?

[wachtwoord]

ok I will buy any 1 btc regardless of its history for 0.9 of my own minty fresh btc.. any takers? 

Thank you for proving my point: you just described the business of coin laundering ass-backward.

If coins were fungible, why would coin laundering service exist and get used ?

paranoia? 'just in case' from heavy silkroad sellers? if the y2k bug wasn't going to happen why did 'electronic preparation' services exist and get used?

You should go peddle your notion that coins are fungible to heavy silkroad
sellers and that coin laundry services aren't necessary. See what they say.

For criminals it is likely to be useful in some jurisdictions. I am not a criminal.

[BlackBison]

znort i do agree with your statement that bitcoin is not fully anonymous- fine by me im not doing anything illegal with mine.

however, your conclusions about lack of fungibility do not follow from this. the most likely reality if your story came true is if there was a node network that linked a criminal purchase to some addresses, they would follow the 'chain' to the exit point (mt gox, purchase of gold, whatever) and go arrest that one guy/group.

if they have sufficiently powerful network analysis tools like you make out, it should be pretty clear who has received dirty coins from regular business through no fault of their own. these people would be safe, and so no1 would care about dirty coins... except the criminals.

this is why i doubt there will ever be any serious fungibility issues with btc. obviously it is possible that i am wrong, but at this point in time this view is the only logical one imo..

[aq]

So the question then is: do you think federal reserve notes (as an example because our European equivalent is just the same) are fungible? Because if Bitcoins aren't the same is true for the bills in your wallet. Even more so as they are split in portions which are predetermined by a central issuer and numbered to be uniquely identifiable.

I think the answer here is that it is a matter of degrees. How fungible is something?

Sorry, but here you are flat out wrong. Greenbacks or euros are *far* more fungible
than bitcoin. The reason is simple: if I give you a euro, only two persons ever know
about that: you and me.

If I send you a bitcoin, the whole word is immediately informed that the transaction
took place, and the transaction is for ever recorded in the great immutable, shared
bitcoin ledger in the cloud, which is available to all for all times for consultation.

Use something like the send anonymous feature at blockchain.info, where you are guaranteed that all of the coins received are not from you. Now how do you find this transaction in the public block chain?
And quite similar to the cash example above, only a few selected know about this. Sounds as anonymous and fungible as cash to me.

[FreeMoney]

So the question then is: do you think federal reserve notes (as an example because our European equivalent is just the same) are fungible? Because if Bitcoins aren't the same is true for the bills in your wallet. Even more so as they are split in portions which are predetermined by a central issuer and numbered to be uniquely identifiable.

I think the answer here is that it is a matter of degrees. How fungible is something?

Sorry, but here you are flat out wrong. Greenbacks or euros are *far* more fungible
than bitcoin. The reason is simple: if I give you a euro, only two persons ever know
about that: you and me.

If I send you a bitcoin, the whole word is immediately informed that the transaction
took place, and the transaction is for ever recorded in the great immutable, shared
bitcoin ledger in the cloud, which is available to all for all times for consultation.

Suppose there was a list containing the time and amount of every cash transaction ever. Would it be useful for catching criminals?

[dree12]

So the question then is: do you think federal reserve notes (as an example because our European equivalent is just the same) are fungible? Because if Bitcoins aren't the same is true for the bills in your wallet. Even more so as they are split in portions which are predetermined by a central issuer and numbered to be uniquely identifiable.

I think the answer here is that it is a matter of degrees. How fungible is something?

Sorry, but here you are flat out wrong. Greenbacks or euros are *far* more fungible
than bitcoin. The reason is simple: if I give you a euro, only two persons ever know
about that: you and me.

If I send you a bitcoin, the whole word is immediately informed that the transaction
took place, and the transaction is for ever recorded in the great immutable, shared
bitcoin ledger in the cloud, which is available to all for all times for consultation.

I asked for change once. Someone gave me change, and I thanked him for his generosity. I tried to spend the money. The cashier said it was counterfeit.

In practice, greenbacks or euros are just as non-fungible as BTC.

[rjk]

Sorry for the OT, but reading this topic made me reaffirm my hate for Znort's annoying habit of using far too many linebreaks. What's the story behind that, anyways?

[scintill]

Znort's annoying habit of using far too many linebreaks. What's the story behind that, anyways?

The decades-old way that Internet messages have been broken into paragraphs?

Edit: Ah, sorry, I see he wraps his lines pretty short in addition to putting breaks for paragraphs.  Wrapping to ~80 chars is also an old Internet practice, maybe that's why Znort does it.

[dree12]

Znort's annoying habit of using far too many linebreaks. What's the story behind that, anyways?

The decades-old way that Internet messages have been broken into paragraphs?

The days before word-wrapping, heh. My email client still attaches newlines automatically, and it's 2012. Makes editing drafts a pain...

[BkkCoins]

Is there a valid reason that the IP address needs to be encoded in new blocks? Couldn't the same transactions be locked down without the IP? I may be forgetting something as I tend to do that but I don't think any of the cryptography and security of the blockchain depends on IP info. So wouldn't it be trivial to just not encode it any more.

And also, if you use an online wallet doesn't the IP stored end up being theirs, not yours. And if you created raw transactions offline and pasted them into blockchain.info's /pushtx page wouldn't that also be true?

If people want anonymity so much then why don't they start a series of pushtx servers similar to Tor nodes that bounce transactions around before giving them to some random bitcoin node. That would make the IP record totally useless.

Someone could easily make a standalone pushtx client that will select a random bitcoin node to emit it's transaction into. Not only would this allow sending anonymously but it would also provide plausible deniability to every other transaction on the network.

All of these things can be done without the official satoshi client devs needing to be involved and can't be stopped by them. So if being anonymous is important why not do it rather than ranting on the forum.

[scintill]

Is there a valid reason that the IP address needs to be encoded in new blocks? Couldn't the same transactions be locked down without the IP? I may be forgetting something as I tend to do that but I don't think any of the cryptography and security of the blockchain depends on IP info. So wouldn't it be trivial to just not encode it any more.

And also, if you use an online wallet doesn't the IP stored end up being theirs, not yours. And if you created raw transactions offline and pasted them into blockchain.info's /pushtx page wouldn't that also be true?

If people want anonymity so much then why don't they start a series of pushtx servers similar to Tor nodes that bounce transactions around before giving them to some random bitcoin node. That would make the IP record totally useless.

IP address is not reported in blocks.  The services that report it are guessing based on where they first saw the transaction broadcast from.

[BkkCoins]

IP address is not reported in blocks.  The services that report it are guessing based on where they first saw the transaction broadcast from.

It must get recorded somewhere in the blockchain as a service can't guess for transactions that happened before they were actively monitoring the network.

The IP does seem totally useless though and I don't see how any sense can be made of it by authorities anyway. I just looked at my recent transactions. The ones coming to me are recorded on blockchain.info as being relayed by an IP physically off the coast of West Africa. And the one I spent a week ago has an IP recorded as being in Sao Paulo, Paraguay. Both totally nonsensical despite my actual IP being easily and accurately reported by most GeoIP services I've seen.

[scintill]

IP address is not reported in blocks.  The services that report it are guessing based on where they first saw the transaction broadcast from.

It must get recorded somewhere in the blockchain as a service can't guess for transactions that happened before they were actively monitoring the network.

The IP does seem totally useless though and I don't see how any sense can be made of it by authorities anyway. I just looked at my recent transactions. The ones coming to me are recorded on blockchain.info as being relayed by an IP physically off the coast of West Africa. And the one I spent a week ago has an IP recorded as being in Sao Paulo, Paraguay. Both totally nonsensical despite my actual IP being easily and accurately reported by most GeoIP services I've seen.

Tracking transactions to IP addresses was never an intentional feature of Bitcoin, so it is not in the blockchain.  Here's an early transaction on blockchain.info, before the site was started.  The IP is bogus 0.0.0.0 because blockchain.info wasn't around to guess an IP, and it's not part of the blockchain.

This is why your reported IP's are incorrect; it's difficult to tie a transaction to an IP.  To be on the safe side, we should assume a powerful, motivated attacker (e.g., NSA, CIA, FBI), could be well-connected enough to see the first time a transaction is broadcasted and hence infer the origin IP with high confidence.  This can be mitigated with Tor etc., but is not built in to Bitcoin.

Edit: forgot to insert this source:

No, IP addresses are not stored in the blockchain.

But Gavin Andreson indeed notes that

Unless you are very careful in the way you use Bitcoin (and you have the technical know-how to use it with other anonymizing technologies like Tor or i2p), you should assume that a persistent, motivated attacker will be able to associate your IP address with your bitcoin transactions.

[sunnankar]

to coins you own, trust me, you *are* going to have to defend yourself.

znort987, you have assumed a fact not in evidence which is 'ownership of bitcoins'. I suppose it depends on what the definition of is is.

Nevertheless, I think znort987 is raising some very good issues about how one should prepare for future interactions with the police state. I highly recommend people watch BUSTED: A Citizen's Guide To Police Encounters. If you have a police encounter in a foreign country then demand to speak with an attorney and the embassy for the passport you entered the country on.

I think the anonymity and fungibility issues znort987 is raising are important although not necessarily imminent. There is a lot of value to severing the audit trail and sending an investigator on a wild goose chase. This is what the mixing services do. Think of all the time and resources it takes chasing down bad leads. If Bitcoin does anything well then it would be creating thousands and thousands of bad leads, a true force multiplier. Sure, an investigator can chase down a crook but there are going to be a tremendous amount of completely innocent people he has to weed through while trying to accurately identify the crook. Even the State's resources are scare and will therefore be allocated to the highest priority targets. So, don't be one of those targets! Nevertheless, in this way Bitcoin can create plausible deniability.

For example, have a laptop you bought with cash with full disk encryption, have a TrueCrypt volume with a hidden partition and within the hidden partition have your Bitcoin application. Then wear a hoodie and sunglasses while you connect to the Internet from a public WIFI network with TOR outside the vision of any cameras. Then open the TrueCrypt volume and transact via Bitcoin. When finished close the volume and power down the laptop. To create even more circumstantial evidence in your favor have your alibi take your cell phone, which uses Silent Circle, for a walk on the beach.

It is going to be extremely difficult to prove to the standard required for a criminal conviction that any particular person was the person that initiated the transaction.