Economically Unspendable Outputs: A Problem On The Radar

[misterbigg]

"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

[gmaxwell]

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).

It can _technically_ be spent it's just uneconomical to do it— the marginal cost (fees/lost of priority/etc) of including it in a transaction will be less than its worth. If you pruned it and then some smart alec went and spent it (costing himself coin in the process) you'd reject the chain and end up on a fork, which mr. smart alec might find profitable indeed (e.g. if you were a competing miner or a victim he wanted to attack).

[CIYAM]

I think calling the amounts "unspendable" is not technically correct - provided an unspent output is old enough even one that contains a single Satoshi can be spent (at least that is the case currently AFAIA).

[Severian]

> 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

[Bit_Happy]

Refrain from playing SatoshiDICE, since you cannot win long-term.

[Meni Rosenfeld]

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.

[CecilNiosaki]

This would be taking action against a problem who is only a problem due to how to network currently operates. If you remove SDice from operation, another company will take its place. We should be happy that SDice has made this flaw apparent and take action not against SDice, but at the source rather than the "cause".

[misterbigg]

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.

We're not asking them to not use Bitcoin, we're asking them to stop exploiting a temporary weakness for personal gain. Especially when a principal is a sitting board member of the Bitcoin Foundation.

[edmundedgar]

"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."

Out of interest, how high do you think the fees would have to be to make their 1-satoshi transactions economically unviable? It strikes me that these guys are making out like bandits doing what they're doing - fees would have to get seriously high to break their (simple and apparently unbelievably profitable) business model. If you think a "mature" Bitcoin is going to price these guys out of doing what they're doing, it's going to price a lot of other uses out as well - probably to the point where we need to give up and go back to the drawing board.

[Severian]

Pressuring SatoshiDice is a band-aid, not a solution.

Elsewhere, I brought up the issue of consent. I didn't consent to host a gamebot's traffic when I run the client, I was consenting to hosting Bitcoin's traffic. If Bitcoin traffic is now a subsidiary of SD's load, perhaps SD can be persuaded to start its own blockchain and stop taking advantage of the implied consent of others on this blockchain.

I doubt that SD can be shamed into stopping what they're doing but perhaps some users of the network can be persuaded into not giving them anymore business.

[Bowjob]

We will end up with a bloat chain problem sooner or later even with 1 MB limit. For now, and to buy the developers some time, I suggest a 0.1 BTC minimum bet on all bets or GTFO. That should reduce the amount of bloat. I had my TX wait for over an hour last night, it wasn't very fun.

[misterbigg]

Out of interest, how high do you think the fees would have to be to make their 1-satoshi transactions economically unviable?

Actually I think this can be calculated from the "max bet" in the 1dice address. For "lessthan 64,000" the max bet is 500 so the fee would have to be a little bit under 500...so yeah the fees would have to be quite high! Unless my math is off.

[maximian]

As has been said many times before, trying to block SatoshiDice transactions is like rearranging deck chairs on the Titanic.

If it's not SatoshiDice that's generating "transaction spam", it'll be something else, and then something after that, and so on. Are you going to launch a new campaign against each?

Also, it's ignorant to vilify the very individuals (Erik Voorhees, Roger Ver, Jon Matonis) who, by their tireless evangelizing, are probably most responsible for making Bitcoin as popular as it is today. If you hold any bitcoins and are enjoying their current value, you owe the aforementioned a debt of gratitude.

[misterbigg]

If it's not SatoshiDice that's generating "transaction spam", it'll be something else, and then something after that, and so on. Are you going to launch a new campaign against each?

It's a good point. This campaign is only an interim measure until robust technical solutions are rolled out. These solutions should not single out SatoshiDICE but rather, focus on the undesired behavior (unspendable low value transaction outputs). This will solve the problem network wide instead of just fixing it for one vendor.

[uhoh]

If a small website that 99.9999999% of the world population don't even know about is causing a problem for Bitcoin, then what hope do we have. You don't fix a problem in a p2p payment network by politely (or impolitely in this case) asking them to please stop. That's, of course, assuming that this even IS a problem. I agree with Mike. They're the only site that's really testing the real world (as in wide adoption) stability of the network.

If SDice is considered an attack on Bitcoin, Then Bitcoin itself is flawed.

EDIT: I will add, I cannot for the life of me understand why people are willing to play a negative EV game, with a currency that was worth $13 2 months ago and $42 today... It defies all logic. 

[Bit_Happy]

...
If SDice is considered an attack on Bitcoin, Then Bitcoin itself is flawed.

Uh-oh, uhoh has a good point.

[bigbox]

Elsewhere, I brought up the issue of consent. I didn't consent to host a gamebot's traffic when I run the client, I was consenting to hosting Bitcoin's traffic. If Bitcoin traffic is now a subsidiary of SD's load, perhaps SD can be persuaded to start its own blockchain and stop taking advantage of the implied consent of others on this blockchain.

I doubt that SD can be shamed into stopping what they're doing but perhaps some users of the network can be persuaded into not giving them anymore business.

I didn't "consent to host" a pot smoker's traffic, so we should figure out a way to block Silk Road's transactions.

I didn't consent to host traffic for a site selling adult toys, so we should block Bitcoinin.com's transactions.

I didn't consent to host traffic related to adult content, so we should block transactions from all the porn sites.

I know somebody that is a luddite, so out of deference to him we should block transactions from electronics resellers like bitcoinstore.com.

I've never used SatoshiDice, but I'm not sure I like vilifying certain types of transactions. That said, I wouldn't mind if SD could figure out a way to lower their load on the network.

[uhoh]

Elsewhere, I brought up the issue of consent. I didn't consent to host a gamebot's traffic when I run the client, I was consenting to hosting Bitcoin's traffic. If Bitcoin traffic is now a subsidiary of SD's load, perhaps SD can be persuaded to start its own blockchain and stop taking advantage of the implied consent of others on this blockchain.

I doubt that SD can be shamed into stopping what they're doing but perhaps some users of the network can be persuaded into not giving them anymore business.

I didn't "consent to host" a pot smoker's traffic, so we should figure out a way to block Silk Road's transactions.

I didn't consent to host traffic for a site selling adult toys, so we should block Bitcoinin.com's transactions.

I didn't consent to host traffic related to adult content, so we should block transactions from all the porn sites.

I know somebody that is a luddite, so out of deference to him we should block transactions from electronics resellers like bitcoinstore.com.

I've never used SatoshiDice, but I'm not sure I like vilifying certain types of transactions. That said, I wouldn't mind if SD could figure out a way to lower their load on the network.

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.

[solex]

Fantastic OP. I agree 100% with it.

Don't forget that even if SD starts internalizing all its business, like Mt. Gox and other major sites, that SD-clones could kick-off at any time and do similar long-term damage to Bitcoin.

The solution is employing even smarter anti-spam filtering for miners which reduces this type of transaction flow to a maximum percentage of "normal" flow, at most 50%, probably a lower target, perhaps 20% is best.

[koin]

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

source?