Economically Unspendable Outputs: A Problem On The Radar

[misterbigg]

The principals involved in SatoshiDICE are [...] and Jon Matonis

source?

Currently it is hearsay.

[Astro]

If the network can't handle the load from SD then we should all just pack it in and go home.  You ain't seen nothin' yet.

[Monster Tent]

> Put pressure on SatoshiDICE to stop the transaction spam. The principals involved in SatoshiDICE are Erik Voorhees, Roger Ver, and Jon Matonis (board member and secretary of the Bitcoin Foundation. See a conflict of interest?

I'm a lifelong member with regrets at having joined but for the fact that Gavin gets paid. It's the only reason I didn't press for the return of my bitcoins.

Email them if you're so inclined:

For Press Inquiries

    Executive Director Peter Vessenes: peter@bitcoinfoundation.org
    Secretary Jon Matonis: jon@bitcoinfoundation.org

Individual Member Class Questions

    Secretary Jon Matonis: jon@bitcoinfoundation.org
    Chief Scientist Gavin Andresen: gavin@bitcoinfoundation.org

Corporate Member Class Questions

    Vice Chairman Charlie Shrem: charlie@bitcoinfoundation.org
    Board Member Mark Karpeles: mark@bitcoinfoundation.org

Legal Questions / Contact

    Chief Counsel Patrick Murck: patrick@bitcoinfoundation.org

General Questions

    Assistant Director Lindsay Holland: lindsay@bitcoinfoundation.org

What is your source on Jon Matonis owning SD ?

[cedivad]

This topic is a good reason for bears to be bears.

[fergalish]

How about a solution like this. A transaction can include outputs that anyone can spend, without requiring a private key to unlock; let's call them "free" outputs. So, the smaller any single output is, the more free outputs the transaction must have, with each free output equal to the standard transaction fee.

Obviously the free outputs will be claimed by clients that relay or mine the transaction. Some clients might not relay the transaction if all the free outputs are already taken, therefore in the interest of propogation, a single relaying client will not be tempted to immediately claim all the free transactions.

However -- I'm not sure about a technical aspect of this. Suppose I send a transaction with two free outputs. The first relay claims one and leaves another blank. The transaction is then mined, so the miner claims the second. However: could the miner also *erase* the claim on the first free output, and insert a new claim on it?  In other words, can the original transaction be derived from the one in which the first free output is claimed?



An alternative solution is this. At the moment, the fee is TXFEE * TXSIZE, where TXFEE is 0.0005BTC and TXSIZE is measured in kB, right?  And the fee must be applied if: a) the priority is low b) TXSIZE > 1 or c) any output < 0.01 BTC. How about changing the fee to:  TXFEE*TXSIZE + SUM_{OUTPUTS<0.01}(TXFEE*log2(0.01/outputvalue)).  Let me explain:

TXFEE*TXSIZE is the same as before.

0.01/outputvalue = 1.0 if outputvalue=0.01
                        = 2 if outputvalue=0.005
                        = 8 if outputvalue=0.000125
and so on.

log_2(...) = 0 if outputvalue=0.01
              = 1 if outputvalue=0.005
              = 3 if outputvalue=0.000125
and so on

So, for each output below 0.01BTC (threshold which depends on bitcoin value, currently ~$40), every time the output halves in value, the transaction fee must increase by TXFEE.

So, a 750Byte transaction with outputs (0.5, 0.01, 0.009, 0.001, 0.00000001) will require a fee on the last three outputs only:   TXFEE*[log2(0.01/0.009) + log2(0.01/0.001) + log2(0.01/1e-8)] = TXFEE*[0.15 + 3.32 + 19.93] = 23.4 * TXFEE.

As you can see, the 1 satoshi output really costs alot of fees.

The problem is that this will merely make the transaction more expensive benefiting the miner - it will not reward non-miners for having to store, relay and validate the output (though that might be impossible anyway).

[kerogre256]

"Transaction spam" is the largest issue threatening the fledgeling currency called Bitcoin. A brief synopsis of the problem:

"SatoshiDICE" notifies gambling addicts of losing bets by sending them a transaction containing 1 satoshi back to their original address. A regular transaction fee is also included in this transaction. The problem is that this produces an unspendable and unprunable output. The output is unspendable because it is so small that it would cost more in fees than it would to send. It cannot be pruned because it has to stay around in fast storage to detect double spends, even though ironically it cannot be spent (developers, let me know if this description is technically accurate).

The immense volume of SatoshiDICE transactions crowds out regular transactions, driving up fees for normal users. This would almost be okay if SatoshiDICE was bringing in new users to Bitcoin in proportion to its increased transaction volume. But most of these transactions come from automated bots running 24/7 spending tiny amounts of Bitcoin. Miners have a love and hate relationship with this transaction spam. They love the fees, but hate that they need to store every one of these transactions on the hard drive, FOREVER. They cannot be pruned since they are unspent outputs. But what's the real problem?

The problem is that SatoshiDICE is taking advantage of the early stage of Bitcoin, at a time when transaction volume is too low to fill the blocks and bring fees up to a level that would make up for the drop in subsidy. If Bitcoin was fully mature, it will not be vulnerable to this type of transaction spam and no one would be talking about it let alone suggest patches, because fees would make the dust spam economically unviable.

We do not have a mature network, and we're in the bootstrapping phase. SatoshiDICE is consuming the "startup capital" (current state of low fees, high subsidy, and lots of free space in blocks) to profit without bringing a corresponding increase in growth of Bitcoin adoption. The simple fact is that a relatively small handful of gambling addicts and bots are flooding the block chain with 70%+ of its transactions.

What can you do to help?

* Put pressure on SatoshiDICE to stop the transaction spam. The principals involved in SatoshiDICE are Erik Voorhees, Roger Ver, and Jon Matonis (board member and secretary of the Bitcoin Foundation. See a conflict of interest?

* Show your support in asking the MPOE exchange where the S.DICE security is located, to de-list the security until the problem is addressed.

* Appeal to the S.DICE shareholders to pressure MPOE to de-list S.DICE.

* Ask BlockChain.info to remove the playable direct links to SatoshiDICE from it's wallet service as a courtesy to the network

* Vote Jon Matonis off the board of the Bitcoin Foundation at the next election.

* Apply suggested patches and updates to your client or mining software to protect the network.

With your help and the rest of the community we can work together to see Bitcoin through this fragile early phase on to see the next generation of cryptocurrency and digital payments!

Thanks

Are you for real ? What is difference between transfering 1 bitcoin and 1 shatoshi for netowork?, there is no difference .... If for bitcoin network, one web page is problem then better sell all your bitcoin now, if bitcon become global suces 99.99999% transaction will be done in Satoshi.

[kerogre256]

So, for each output below 0.01BTC (threshold which depends on bitcoin value, currently ~$40), every time the output halves in value, the transaction fee must increase by TXFEE.

LOL
Bitcoin value for me is pricless now please put it in code....

[fergalish]

So, for each output below 0.01BTC (threshold which depends on bitcoin value, currently ~$40), every time the output halves in value, the transaction fee must increase by TXFEE.

LOL
Bitcoin value for me is pricless now please put it in code....

Would be reviewed periodically by developers - much like the transaction fee, now at 0.0005BTC. If bitcoins jump to $100 or $200, the minimum transaction fee will probably be reduced to 0.0001BTC. What I mean is, with fiat currency, there is a minimum transaction - $0.01.  Actually, in Canada, isn't it CAD$0.02 ?  I gather some European countries don't even use €0.01 coins anymore.

So the devs would introduce a minimum recommended transaction output of 0.01 BTC. According as 1 BTC buys more and more potatoes, the minimum transaction should be reduced accordingly. In any case, the minimum transaction output should ALWAYS be greater than the minimum transaction fee, so that these spammy outputs can always pay for their own redeeming and be eventually pruned.

[lophie]

@fergalish

Su you are saying lets start giving specific individuals powers to control aspects of Bitcoin and change things as "they see fit"....... remind me again why do we believe Bitcoin is different than the other crap outthere?

- Edit, Just noticed you mean periodically change the "recommended" fees. Sorry that would be totally okay IMO.

[ShadowOfHarbringer]

* Put pressure on SatoshiDICE to stop the transaction spam. The principals involved in SatoshiDICE are Erik Voorhees,

If he can spam Bitcoin network that means its a vulnerability. Vulnerability that needs to be fixed.

It is pointless to "put pressure" on anybody. On the contrary, its good that somebody shows us what needs to be improved. SatoshiDICE is not our enemy, just an opportunist using an opportunity.

If ever governments decide that they don't like Bitcoin after all, SatoshiDICE will be the least of our problems. A real enemy like that will use any means possible (including spamming the network) to harm BTC.

So perhaps let's grab this opportunity to harden the Bitcoin protocol instead of complaining.
.
.

Pressuring SatoshiDice is a band-aid, not a solution. The Bitcoin system is supposed to work, we're not supposed to ask people to do us a favor and not use it.

To solve the problem of unprunable small outputs, we need some form of output upkeep costs.

+1

[Mike Hearn]

I've never heard of anyone except evorhees being involved with SatoshiDice. You should really be careful with throwing names around like that.

[phelix]

Is there a particular reason fees higher than the transaction value are allowed?

What about imposing this:

Smallest output must be at least 10 times the fee.

It would always ensure that it is possible to spend output, thus allow pruning.

[oleganza]

"Transaction spam" is the largest issue threatening the fledgeling currency called Bitcoin.
(...)
Miners have a love and hate relationship with this transaction spam. They love the fees, but hate that they need to store every one of these transactions on the hard drive, FOREVER. They cannot be pruned since they are unspent outputs.
(...)
We do not have a mature network, and we're in the bootstrapping phase. SatoshiDICE is consuming the "startup capital" (current state of low fees, high subsidy, and lots of free space in blocks)

What a load of nonsense. I myself do not care about SatoshiDice at all, but seeing people making a drama about it makes me itchy.

First, it's your subjective opinion what is "spam" and what is not "spam". Miners voluntarily include transactions they want and voluntarily accept blocks from other miners. They account for their storage costs themselves without asking your opinion. If the disk is scarce for you, do not store the whole blockchain. My phone disk space is valuable for me, so I don't keep the whole blockchain there. Maybe I should complain to the Pope or Mr. President that there are too many transactions out there for my phone to handle?

Second, it's your subjective opinion regarding the "maturity" of the network. For me Bitcoin is not even "beta", but already proven and working protocol. You may disagree, but I don't see how my opinion should block your transactions and your opinion should block mine. It's up to actual miners and every other single user to decide whether to verify/include/relay/store/prune transactions. And everyone will decide for themselves individually. I may prune some transactions from the blockchain, you may choose to have block headers only. Or we can store random 1% of all transactions and download more only when needed from the peers around.

Third, "startup capital" does not exist. As does not exist any "common good". Good is always evaluated subjectively and individually. There is no "society" entity acting on its own. It is just a name for a bunch of people acting in their own self-interest. SatoshiDice consumes only the resources that somebody is willing to sell and others are willing to pay for. There is no "danger" whatsoever. You are basically calling for censorship based on your personal preferences, disguising them under "common good" myth. This strategy is very dishonest and reminds me of shitload of propaganda that is poured on every single person all around the world for the last several thousand years.

[mobile4ever]

Well put. What's the point of this whole experiment if we're just going to pull a VISA and block any entity we don't agree with.

Because we are to free block things we dont like. We are in this together.


But, doesnt this news mean we could use a few more nodes? With seven billion people in the world, the total amount of transactions needed can be averaged out, even taking the "spam" uses into account.


One of the more higher-ups than me, who is probably a member of the Bitcoin Foundation, said the blocks need to be made bigger and started telling folks to change settings and to reject some traffic.


Whatever we do, lets fix this. If more nodes will work, lets do it, if rejecting some traffic that is unacceptable to the community will fix it, lets do it. If we are all washed up here, and there really is no problem, lets find that out as well.

[justusranvier]

The problem of unspendable outputs can be fixed with dust collection algorithms in the clients.

With every transaction the coin selection algorithm can check to see if any dust outputs can be included as an input without causing the transaction to require a higher fee.

[Killdozer]

You n00bs! As always, gambling services = plausibly deniable money laundering. Wink

Right now, the whole fucking Bitcoin network is plausibly deniable money laundering 

[Rygon]

Miners are the ones with the voting power here. Specifically, that voting power is weighted based on their ability to quickly download blocks and transactions, solve blocks, and then push the blocks out to the network. Right now, this is based on their hashing ability. If the blocks start to become too large because of transaction volume, it could take minutes instead of seconds to push around all that data over networks, which would impact the speed of solving blocks. If the fees aren't high enough, the miners may decide to start pruning out transactions in order to gain a leg up on the competition. AFAIK, we aren't there yet, except for a few pools that don't include SDICE transactions.

I don't think we have a real issue until the average fee that the miners demand for inclusion in the blockchain becomes too large for most of the users on the network. The likely reaction to that would be for specific applications to move their traffic onto internal networks, which would take some load off the blockchain. If the network became too fractured, then obviously that could be a potential flaw.

And if you want to block transactions going to/from SDICE, you really ought to be convincing the mining pools to reject them or charge higher fees, since they are the only ones who can do something about it.

[WiW]

I don't see the problem. Raise the max block size limit and problem solved.

SDice is only sending so many txns because it's cheap. When it becomes expensive, they'll stop (or find some other creative way to do what they do). People will use the blockchain however they're allowed to. All you're saying is that you don't trust the design of bitcoin to handle this stuff and you want a centralized "solution" to something you don't like on the network.

Go use fiat.

[nebulus]

Sorry but thread title is misleading.

[ShadowOfHarbringer]

"Transaction spam" is the largest issue threatening the fledgeling currency called Bitcoin.
(...)
Miners have a love and hate relationship with this transaction spam. They love the fees, but hate that they need to store every one of these transactions on the hard drive, FOREVER. They cannot be pruned since they are unspent outputs.
(...)
We do not have a mature network, and we're in the bootstrapping phase. SatoshiDICE is consuming the "startup capital" (current state of low fees, high subsidy, and lots of free space in blocks)

What a load of nonsense. I myself do not care about SatoshiDice at all, but seeing people making a drama about it makes me itchy.

Exactly. This whole thread is complete bullshit and waste of time.