Bitcoin Forum

After someone "mines" a block, any transactions with fees going through the block will earn the block owner some money. But is there a way to trade blocks? for example, i give someone 60 BT, in exchange for a block that he owns. the owner then relinquishes control of that block, and sends it to me, and he pockets 10 BT.

Theoretically yes, but since it's a race with a half life of 10 minutes, you should be quick or somebody else will solve the block.

Eh, I guess there are two ways you might try to do this. First the impossible way: You take his valid block and replace his address with yours so you can receive the reward instead of him; this fails because changing that will change the hash of the block and it won't be valid anymore. Second he could send you the private key that goes with the public key that is being assigned the reward. You will not be sure that he doesn't retain a copy of the key so you should spend the coins to a new address of your own. But if you are going to do this then you might as well let him get the coins and send them to your new address himself.

Maybe I'm missing your point, but I don't think there's any reason to try any of this.

if block trading was possible in the future, there might be people who buy blocks as an "investment", because they pay a "dividend" (transaction fees)

What would the point of that be? A block isn't worth anything in and of itself. The only value it has is the 50BTC plus transaction fees the miner receives. You'd be out 10BTC.

Maybe you are missing the fact that the transaction fees are completely know when the block is solved? There is no recurring fee or anything.

Maybe you are thinking of paying a miner now for, say, the first block they find after block 220k or something? Essentially making a bet on the fee activity in the future? Probably the best way to make this bet would be to buy or contract for mining equipment.

sorry, my mistake. I thought fees were recurring.  :-[

I mean new fees keep being paid on new tx, but for any one tx there is one fee which is chosen and attached by the sender.

It does have potential value above the value of just the 50 BTC in that the coins are brand new and have no transaction history associated with them.

Can't we drop the probably and just say no here? The only way to assign those 50 btc to a new address is to redo the work for the block with the new address... and every block thats happened since then. So, while I see the value of "clean" btc, that value only exists for the original finder.

Whether he gives you the key, or redoes the block via some secret magic, he still knows that he redid it for you, so they are no longer clean for you.... but none of that matters because, since they went to an address that nobody has ever seen, but him, nobody knows that he is the one who generated it. So if you know a guy that you trust enough to buy a block from, you may as well just get the coins from him.

If it could be done, it would break the entire system, since the foundations of transaction security rest on the fact that blocks don't change (except at the really shallow end, and then only rarely).

I think what you COULD do (and this probably requires some minor changes to the client to pull off), is pre-generate a key, and pay your btc mining friend to use that key in his work, so that when he finds a block in the future, its value is assigned directly to you. It wouldn't garauntee you any specific block number, and would have to wait until he finds one.... but, that seems to fit within how I understand the protocol. I think he should only need the public key for that? Am I right?

Would be interesting.... I pay you btc up front for the next block you generate.... as long as you find it before the block value drop, I get 50 btc + any fees.... interesting gamble, I could see it working out. Be an interesting way to do a mining contract or pay for hardware upgrades.

The first pool did this to pay members directly and immediately. It's cool because that lets members verify that they are working on a block that will definitely pay them.

I actually thought of the idea of selling my blocks at a profit but for a different reason.

Virgin unspent blocks are more anonymous than blocks that were acquired any other way.  If I were to go buy BTC from a brick and mortar Bitcoin dealer that "knows your customer" and then I go use it to buy drugs or something, there's a link.  Maybe one wouldn't chase it for drugs, but for something more heinous, maybe.

A freshly generated block has absolutely no history...

Makes no sense. If you are buying blocks, the seller knows you just like if buying BTCs.

Sure but, if you can mix them in with coins that have passed through other hands, is that not just as good?
Possibly better, since backwards attacks are possible. Consider this, you buy drugs with btc from a mined address.

Now the rest of your coins, mined from that block, are all tainted with your drug transaction, and can still give you away back to that transactions when you otherwise sell them.

Maybe you worry less about this? Maybe not? In any case: https://en.bitcoin.it/wiki/Anonymity

Is an excellent link

Not if you operated some swap site that allowed people to anonymously participate.

Suppose the overall majority of BTC trading ends up being drugs (a plausible possibility if word of BTC spreads like wildfire across drug users)... there won't be enough "clean" coins to really dilute the history.

In fact, there'd be a disadvantage for large sellers: if BTC were overwhelmed with drug-related popularity, a "fed" could merely spend 5 BTC on a little pot, and then watch where that 5 BTC went, and as those 5 BTC got combined and mixed around, they could arguably claim that every other BTC that the original 5 touched or mixed with soon thereafter is also drug money.  So if 45000 BTC hit a local exchanger that included that 5 BTC, they'd be making life miserable for the exchanger.

How is this different from transferring the coins from an unspent block to a brand new address?

Assuming the anonymity provided by a mined block has some value to the buyer, the miner could just transfer 50 BTC from the unspent block to the buyer's address and receive 60 "dirty" BTC from the buyer.
They just have to be careful that the coins don't get mixed.

Well, they can claim it, but no reasonable person should believe him.

Consider the same scenario, but with cash. Bitcoin is, after all, supposed to be a digital analogue (pun intended) of cash.

The fed writes down the serial number of a $5 bill, and uses that to pay for the pot. Suppose he has some magical way of keeping track of every transaction made with that $5 bill. The drug dealer goes to the corner store and buys a bag of chips and a bottle of pop (soda for you Yanks :-). Ten minutes later, a sweet old lady comes in to buy something, pays with a $10 bill and gets the "tainted" $5 as part of her change. That Sunday, she drops the $5 bill on the collection plate at church. The church then deposits its weekly givings at the bank. Do you think any reasonable person is going to believe that the entire collection is drug money? Not likely.

And the fact that you can split a bitcoin makes it even harder to follow its history, because as soon as a bitcoin is split into different coins, particularly if another coin is combined with it at the same time, it's almost impossible to figure out which of the two out transactions contains the "tainted" coin.

From a new block, there wouldn't be a history.  Nobody would know whom to ask where he got his BTC.

Compare to BTC acquired from a reputable exchanger.  It might be possible to tell what exchanger the BTC came from based on other transactions it was combined with.  Someone goes and gives their real name to a KYC-following BTC exchanger thinking they are buying "anonymous money", and then they go do something terrible with it thinking there's no link to the BTC purchase, but there is.  The BTC he bought may very well have enough traceable history that would lead to the place he bought it, there is just no way to know for sure.

At least if he got BTC from a new block, that risk would be greatly lessened, because one could be sure there was no public information available about where the BTC came from.

I highly doubt this scenario, since the majority of drug sales are small transactions. Most any tobacco smoker can buy it by the carton and save money, but, the vast majority choose to pay a premium to buy it by the pack, each and every day, rather than to buy a carton and have a supply for most of a month. As far as I can tell, this holds true for most other drugs, including alcohol. There are always exceptions, but, the majority do it like this.

Also, block processing can take up to 10 minutes each, unless you are willing to take transactions on faith that the confirmations will come, we are looking at up to 20-30 minutes just to hand over the money. This, almost certainly, means that btc will not replace cash for in person transactions.

So where does that leave us? Mail order transactions (I believe someone posted a link to a site called "silk road" recently which facilitates exactly this). This is not appealing to most users, not just for trust reasons, and security reasons, but, because it doesn't meet their immediate desire.

aside from that.... Lets say that some major distributors come online, and there is a sizeable wholesale trade (I see this as a bit more likely). The vast majority of cash *IS* used in drug transactions, right now. It may not be the majority of the markets that its used in, but, the actual dollars themselves, nearly all of them, move through drug transactions at some point.

Every few years the news media rehashes the figure of what percentage of US money tests positive for just cocaine....and its really most of it (I forget the percentage they toss around).

Small transactions which add up to big transactions when the mailers/dealers/manufacturers end up with lots of BTC and few ways to spend it other than to either drop it on the market or buy lots of anonymous web hosting, coffee, alpaca socks and VPNs.  The thing is, BTC's nature is likely to attract black market activity far faster than legitimate business so the need for them to cash out into fiat currency is inevitable.


If there were some website where agencies could trace every dollar serial number, where it's been, and what other dollars it has touched, then that would make the analogy more accurate.  There's a big difference between a hunch that "this could have been drug money" based on a whiff, versus tangible public evidence that can positively establish that the guy who just dropped 45kBTC at XYZ exchanger is a drug dealer, "let's go take him down".

Yes, I understand that.

I was arguing that transferring the coins from the new block to a new address (provided by the buyer) and then using them for whatever shady goal one may have in mind is just as anonymous as using them from the unspent block. They would show one more transaction in their history, but as long as they are not mixed with any other coin there would still be no one to interrogate.

Of course the "not mixing" part may require some attention, and possibly a patched client, but it will still be easier and safer than sharing private keys for the block.

So, I would say that if anonymity is what you are interested in, simply transferring the newly mint coins to a buyer's address is equivalent to actually transferring the block. Or am I missing something?