Identifying "my" transactions

[Gavin Andresen]

From another thread:

I think that if Bitcoin allowed users to insert some identification such as their name or an email into the users transactions then if an attacker stole money from the user it would make it a lot easier to report the theft such as if the attacker tried to change the currency into dollars by exchanging it with a bitcoin trader...

No need to embed the identification in the transactions, I don't think.  You just need to associate your public keys with 'you' at some place where anybody can see that association and prove that you originally owned the private keys associated with those public keys.

Let's see, I think something like this would work:

For every private key in your wallet:
  Grab the corresponding public key
  Sign it with the private key
  Compute SHA256(public key, signature, "your name and email address")

Then upload all of those SHA256 hashes to some secure central database somewhere, which stores it along with the time it was uploaded.

Now if somebody copies your wallet and spends your coins, you can prove that you had the public/private keys in the past by showing everybody the (public key, signature, "your name and email address") that hashes to the value in the central database.

The crook can upload their own SHA256, of course-- this relies on you uploading before the crook.

[BitterTea]

I was thinking about this as well, but then I realized that proving prior ownership doesn't prove that you are still the rightful owner of those Bitcoin. You could have voluntarily traded them to the new owner and then claimed they were stolen from you, no? Once you start automating this, it seems a bit like a chargeback.

[we6jbo]

For the purpose of anonymity your name and email address could be Anonymous null@null.null or any other identity for that matter. I really feel that some kind of identification should be implemented somehow in Bitcoin otherwise I'd fear that if I placed my money into the hand of my wallet and someone hacked my machine, as secure as I keep it, that basically there's nothing that I can do.

[Gavin Andresen]

RE: trading private keys with somebody:  theoretically you could, but that's not typical bitcoin usage and the current bitcoin client makes it hard to do.

Practically speaking, if Bitcoin did have a feature to state:
 "On THIS date somebody using the identifier <foo@bar.com> controlled THIS public/private keypair"

... that would just inspire the smarter bad guys to send stolen coins to new private keys before spending them.

I can imagine a black market forming where dumber bad guys sell stolen wallet.dat files (at a discount) to smarter bad guys (or just plain greedy people who don't bother to ask where the wallet came from), who mix up the coins in them and then sell them.

[we6jbo]

You'd still be able to track the Bitcoins in transit using block explorer.

Example:
Your Bitcoins -> Thief puts your bitcoins on their computer -> Thief transfers bitcoins to private Bitcoin address -> Thief sends Bitcoins to Bitcoin to Gold trader
1. You make a dispute that your bitcoins were stolen on such a data and that you can prove that you were at once time the owner of the Bitcoins
2. Bitcoins to Gold trader sees your dispute and the trail that the thief made through block explorer and puts a halt to the trade until the issue can be resolved.

This system actually solves a lot of problems. Formost it does not require authorities to be involved because all of this can be done by people in the network. It's also a lot better than paper currency because there's always a trail that anyone can follow where as paper currency is pretty much lost. In addition, even if the money goes across state boundaries anyone can still track it.

Of course there's also some problems with the system mainly how do you prove that you did not actually give your money to the "thief". A thief can just as well SSH into your computer, manually transfer the funds that way and then claims that you gave the thief that money. Then again it would be highly suspicious if over night a new bitcoin address received 2000BTC from someone especially if that Bitcoin user runs no known services.

[casascius]

You'd still be able to track the Bitcoins in transit using block explorer.

Example:
Your Bitcoins -> Thief puts your bitcoins on their computer -> Thief transfers bitcoins to private Bitcoin address -> Thief sends Bitcoins to Bitcoin to Gold trader
1. You make a dispute that your bitcoins were stolen on such a data and that you can prove that you were at once time the owner of the Bitcoins
2. Bitcoins to Gold trader sees your dispute and the trail that the thief made through block explorer and puts a halt to the trade until the issue can be resolved.

This system actually solves a lot of problems. Formost it does not require authorities to be involved because all of this can be done by people in the network. It's also a lot better than paper currency because there's always a trail that anyone can follow where as paper currency is pretty much lost. In addition, even if the money goes across state boundaries anyone can still track it.

Of course there's also some problems with the system mainly how do you prove that you did not actually give your money to the "thief". A thief can just as well SSH into your computer, manually transfer the funds that way and then claims that you gave the thief that money. Then again it would be highly suspicious if over night a new bitcoin address received 2000BC from someone especially if that Bitcoin user runs no known services.

Then no one will want to accept Bitcoin, because of the fear that they'll receive Bitcoins they can't use later without their transaction being "halted".

By the way - nice sig line with the green Bitcoin bar - but how's anyone going to be able to read your address when you can't tell which letters are lowercase?  Addresses are case sensitive

[we6jbo]

You'd still be able to track the Bitcoins in transit using block explorer.

Example:
Your Bitcoins -> Thief puts your bitcoins on their computer -> Thief transfers bitcoins to private Bitcoin address -> Thief sends Bitcoins to Bitcoin to Gold trader
1. You make a dispute that your bitcoins were stolen on such a data and that you can prove that you were at once time the owner of the Bitcoins
2. Bitcoins to Gold trader sees your dispute and the trail that the thief made through block explorer and puts a halt to the trade until the issue can be resolved.

This system actually solves a lot of problems. Formost it does not require authorities to be involved because all of this can be done by people in the network. It's also a lot better than paper currency because there's always a trail that anyone can follow where as paper currency is pretty much lost. In addition, even if the money goes across state boundaries anyone can still track it.

Of course there's also some problems with the system mainly how do you prove that you did not actually give your money to the "thief". A thief can just as well SSH into your computer, manually transfer the funds that way and then claims that you gave the thief that money. Then again it would be highly suspicious if over night a new bitcoin address received 2000BTC from someone especially if that Bitcoin user runs no known services.

Then no one will want to accept Bitcoin, because of the fear that they'll receive Bitcoins they can't use later without their transaction being "halted".

By the way - nice sig line with the green Bitcoin bar - but how's anyone going to be able to read your address when you can't tell which letters are lowercase?  Addresses are case sensitive

In that case keeping a transaction record for large amounts is very important. For example, who gave you 2000BC and what did you do to receive that large amount? In addition, the person making the claim would need to prove that the money was stolen. For example, if the person was in possession of a vehicle then that person would need to show where that vehicle came from.

Edit: changing BC to BTC

[BCEmporium]

In that case keeping a transaction record for large amounts is very important. For example, who gave you 2000BC and what did you do to receive that large amount? In addition, the person making the claim would need to prove that the money was stolen. For example, if the person was in possession of a vehicle then that person would need to show where that vehicle came from.

It's a start but needs practical sense... which it lacks. We ALWAYS must be aware of such in a market of trust:

a) Anyone is capable of anything
b) A scammer may not necessarily be the one who holds the coins (buyer) but can also be one waging to get his coins back for free (seller). This means that both the one with the hot coins in hand and the so-to-claim victim can be the scammer in the operation.

Now, on your example, it's impossible to put to practice within BTC. How you can tell if he has or not a new car?! By the way he types in a forum or chat?! Will call his neighbors?! That sort of findings are easy on face-to-face business, but impossible within internet.

[we6jbo]

Bitcoins don't necessarily need to be exchanged through a forum. If I see a car on a used car lot which says for sale 5000BTC and I decide to buy it with anonymous currency and later say that I never made the purchase then I better be prepared to back my statement with no car and no title transfer.
Edit: Changing BC to BTC

[Anonymous]

Possession is 9/10 ths of the law.

 

[casascius]

Suppose I sold somebody a 1 ounce gold coin for 1500 BTC.

I then sent that money to MtGox to do a little trading, and come to find out, that BTC was stolen and it's being frozen.

When asked how I got it, I'd say I sold someone a gold coin, perhaps providing proof of shipping.

I wonder what are the odds that I'd be stiffed.

[we6jbo]

What if the coin was stolen and the police were after it. The person that now has the coin would be out a lot more than 1500BTC

[casascius]

What if the coin was stolen and the police were after it. The person that now has the coin would be out a lot more than 1500BTC

Assume I am not selling stolen coins because they were purchased from a reputable precious metals dealer.

[we6jbo]

Well I would think that proving that you once owned a gold coin and that you shipped it would be enough. I think there would also need to be a lot of credibility to prove on either side. On the other hand if the person claiming the money was stolen was claiming that it happened after receiving the 1500BTC then I don't see how it could harm you in the very least because now it's about someone stealing money and not necessary that the object was never shipped.