Daniel Krawisz, Chief Scientist, MatterPool
Document version 1.0.2
Boost POW is an ungameable content-ranking system and spam filter that uses Bitcoin's[^1] proof-of-work algorithm. The proof-of-work is bought using a Bitcoin output that is redeemed with a nonce, which is a number that completes a proof-of-work string. The work is verified in script. The Boost output can be translated to a Stratum job by a mining pool. The satoshis in this output are payment for doing the work. Boost POW is designed to be fully compatible with the existing Bitcoin mining infrastructure. Thus, it is a new way for the Bitcoin economy to serve the world that all miners can immediately offer.
There are two kinds of Boost outputs: bounty and contract. The bounty output can be redeemed by any miner whereas the contract output can be redeemed only by a specific miner who has agreed beforehand to do the work. The contract job can be expected to be cheaper and more reliable. The price will be determined by the miner. Bounties in bounty outputs, on the other hand, are set by the user without any previous interaction with miners required. For bounty outputs that are not redeemed because the bounty wasn't big enough to entice any miner, the bounty can be increased by creating a second output that is redeemed by the same nonce.
The entire Bitcoin mining industry can immediately support Boost POW. This means that users can estimate energy spent on proof-of-work from the specs of Bitcoin ASIC mining machines and can compare the opportunity cost of any boosted message to the whole hashpower of the Bitcoin economy.
Boost POW puts the onus on the buyer to value information correctly. Those who do not will either get less attention or lose energy. With Boost, there is an immediate need to think ahead in order to optimize attention against conserving energy because of the competition for attention of all ideas. The system is ungameable because buyers will automatically adjust difficulty until manipulation is no longer profitable. The result is that content filtered by proof-of-work will have valuations attached which are on average reliable indicators of the value of the message. Thus, bad ideas die out quicker and all readers get better information.
The first services to integrate Boost are Twetch and Baemail, where Boost will be used as a content ranker and spam filter. These purposes were understood by Adam Back when he originally proposed HashCash.[^2][^3] Boost updates HashCash to use Bitcoin's technology.
The Handicap Principle[^4] tells us that it is rational to pay more attention to messages that demonstrate more opportunity cost, insofar as such messages convey reliable information about the value being offered by the writer of the message. It is easier for the writer to bear the cost if he is offering something of genuine interest to the reader of the message, due to the likelihood of benefit returned by the receiver. The most obvious examples come from sexual selection. It is the principle by which the peahen can reliably assess the peacock by his tail. Many other animals have beautiful displays in males that are used to impress females.
There are many other contexts in which the Handicap Principle is relevant. I have described many examples in my video with Ryan X. Charles. For example, in some species, males are more focused on gaining territory from each other than on impressing females and use handicaps to impress each other with strengths. Horns and antlers allow male animals to oppose each other and learn about one another's strengths in a way that is less dangerous than if they were to fight without them. Thus they are more likely to live to fight another day. The cost that they incur is to bear heavy weapons that prevent them from lying about strength. The Handicap Principle also explains how Bitcoin miners can expect each other to uphold their system instead of exploiting it. A miner can be seen to have hashpower. His best bet to make back the value he has spent is to align himself with the system. Without proof-of-work, other nodes would not know that the miner is in that position.
The Handicap Principle was originally described by Zahavi using plain English[^4]. Later, Grafen developed a mathematical model.[^5] The theory of handicaps can explain a lot about animal communication. Handicaps are such a good way of transmitting information reliably that they appear to be a stable game in nature.
Cryptography gives us a handicap that can be demonstrated over computer networks in the form of proof-of-work. Boost POW is designed based on the hypothesis that using proof-of-work is a stable strategy for people who depend on having good information. If that is true, then among people who use it, bad ideas will die out more quickly.
Proof-of-work has reached its most advanced form in Bitcoin mining. Although the potential applications of proof-of-work are vast, currently Bitcoin miners only use their machines for Bitcoin mining. Satoshi may have only been thinking of Bitcoin when he designed Bitcoin's work function, but the function he designed is good enough for everything. Because of the technology and infrastructure that has been built around Bitcoin since it came out, it is better than alternatives. Boost POW enables machines originally designed for Bitcoin mining to be used for every possible alternate purpose. Bitcoin’s 80-byte block header becomes the Boost signal that associates work with any message. The previous block hash is replaced by the hash of the content on which work is done and the Merkle root is replaced by the hash of a document containing arbitrary metadata.
The Handicap Principle is still controversial in biology because it is difficult to design experiments that rule out all possible alternative hypotheses. It is easy to see what animals do, but game theory explains why they do not do something else. Although there are many apparent examples of the Handicap Principle in nature, it is not easy to show that the reasons that the animals are not doing something other than handicapping themselves has anything to do with Zahavi’s logic. I think that the degree of controversy in biology is unjustified. I do not think that it is possible to get out of the logic of Grafen's paper. It is easy to imagine how handicaps would arise naturally. Someone who does not believe that Zahavi's logic makes sense is free not to use Boost. I predict that person will find themselves worse off due to encountering fewer good ideas and in the end will choose to use it.
In “Biological Signals as Handicaps”[^5], Grafen frames his theory as follows. Let there be a type of message consisting of a value, called the strength of the signal. In Grafen, writers of this message are called males and readers are called females. However, it is not necessary to imagine that senders and receivers are actually males and females or even disjoint classes. Handicaps in sexual selection are simply the most recognizable application. Grafen discusses alternative interpretations in his paper, such as that between males and other males and between predator and prey. In the Bitcoin network, nodes are hermaphrodites because they fulfill both the male and female role. They must both generate hashpower and connect to each other in proportion to hashpower.
In Grafen's model, female fitness varies by how well they assess males. Male fitness varies by a combination of how highly they are assessed by females and some independent quality related to their survival in nature. This independent quality is something that females want to know but cannot observe easily, something that males would want to deceive females about if they could get away with it. For example, how well does he forage for food or evade predators? Males must strategize about how to optimize their total fitness as a function of the strength of the signal they produce. Females must choose how to interpret signals.
In game theory, a strategy is stable if it is in no player's interest to follow a different strategy when everyone else is following it. Stable strategies win out over unstable ones. When more than one stable strategy exists for a game, different ones can win out in different circumstances.
Grafen imagines that there are stable strategies for males and females in terms of how strongly they signal and how they infer fitness from signal strength. He derives three results from this premise:
Result 3 says that the cost of the signal must differentiate males by quality. A signal which does this must directly oppose the male's quality. If it did not, it would not differentiate them as well. This is why Zahavi called it a handicap. If all males could bear the cost of the signal equally, the cost would not provide useful information about them to females. On the other hand, when result 3 is met, a more fit male can always produce a stronger signal than a less fit male at less risk because he will still have more quality leftover than the less-fit male. Thus a ranking is established between males when all of them maximize fitness. A good costly signal creates a contest that is in each male's interest to participate and to attain the highest rank they can afford.
What kinds of costs are good? It depends on what fitness means in the given context. Different species of animals rely on many different skills to survive. The right cost will be different depending on what skill most needs to be emphasized. As Grafen says, "[t]he handicap principle in general suggests that the form of signals may be explicable in terms of what they signal, and conversely that we may find clues about the meaning of a signal in its form."
How easily is Grafen's logic turned the other way? Given a costly signal, can we say that it is a stable strategy to use it to communicate fitness? No, because the benefit of deception may not be good enough in the absence of the signal or because there could be other signals that offer a better trade-off.
We live in a world where manipulation tends to win because our networks are easy to fill up with spam that everybody ends up listening to and getting indoctrinated with. Manipulators operate in a mode where they take control of all information dissemination pathways and fill all content with their lies. Manipulators are like less-fit males because they want attention but have less to offer.
Boost puts manipulators at a disadvantage. Manipulators operate in a mode where they must communicate first before they have energy. Boost requires everyone to have energy before they can talk. Furthermore, it is easier to route around information channels that have been corrupted because people can look for proof-of-work coming from anywhere. Without Boost, more effort is required to evaluate sources of information before listening to them because there are too many sources of information to listen to them all. With Boost, information comes filtered already.
Without Boost, it is easier for a manipulator to keep alternate information away from the people he has conned. With Boost, all information is ranked and people will look at the top ranks, down to however many sources suit their fancy. Everyone wants this ranking because they know they are better off with it. A manipulator may have a lot of money, but someone with stupid ideas cannot maintain control merely by buying up the top rank. A manipulator must have all ranks in order to control information. No one can afford that. Boost is the solution to fake news.
Everyone will know that it is rational to pay more attention to messages with more proof-of-work because they will be able to experience the difference. After Boost, someone who wants to control ideas will have to tell people not to look at messages that are objectively rational on average to listen to.
Boost does not remove the need to use judgement. It just means that it will take less effort to find a good idea. A message with more proof-of-work is not always better. It is only expected to be better on average. Boost is a way of thinking together. Thus it doesn’t really work unless people use judgement. Unlike the systems we use currently, however, manipulators cannot gain the advantage to prevent good judgement from winning out. With Boost, good judgement from many people is more harmonious.
In Bitcoin there is a quantity called difficulty which is proportional to the expected number of trials required to achieve the target. Difficulty is additive. In other words, if two Boost signals exist for the same content, the sum of the difficulties of both strings is proportional to the difficulty of a single hypothetical string which required the same expected number of hash operations to produce as did both real messages together.
For any content there can be many signals purchased by many different people but they can be summed to get a total difficulty. All content can be compared by total difficulty. Thus, proof-of-work is a natural upvote that cannot be gamed. Any opportunity to game the system by spending energy is a better opportunity for an honest actor to gain from the system legitimately.
There is no natural downvote. Such a thing would violate the second law of thermodynamics. Furthermore it would play into the hands of manipulators if it existed. Downvoters want to suppress competing ideas rather than promote their own ideas. Downvoting is deplatforming. With Boost you cannot deplatform. Anyone who can create proof-of-work has a platform automatically because everyone will want to see the message after they verify the work.
Returning to Grafen’s model, it makes more sense to think of the messages themselves as males and all readers as females. Anyone can add proof-of-work to any message in a content-ranking system, so everyone participates in the strategic choices about how proof-of-work is to be apportioned among messages and the messages are all in competition for readers’ attention.
For spam filtering, it makes more sense to think of senders of messages as males and receivers as females. For content-ranking,
As a spam filter, proof-of-work provides assurance to the recipient that messages will be worth reading and to the sender that messages will be read. The recipient sets a minimum difficulty for accepting messages. The best possible value to set the minimum difficulty is the lowest for which you still want to read every message that you receive. This may seem superficially quite different from Grafen’s model but it is easy to apply it if we think of the total strength of the signal produced by each male (sender) to be the sum of all messages which he chooses to send.
A spammer must send many more messages than he receives responses because his messages aren’t worth reading. Proof-of-work requires him to send individualized messages with an individualized cost. As difficulties increase, his profits decline. Someone who actually has worthwhile things to say to people he actually knows will not be overwhelmed by the cost of doing more work than spammers on each message because he doesn’t have to send as many.
Spam filtering may not, at first, appear to satisfy Grafen’s model because instead of competing to produce the strongest signals, senders must satisfy a minimum threshold applied by the receiver. However, Grafen’s model can be applied if we again use the fact that difficulty is additive. The senders can be thought of as males and receivers as females if the strength of the male’s signal is the sum of the difficulties of all messages that he has sent. Under this interpretation a spammer is like a less fit male who tries to produce a bigger signal than everyone else.
Grafen has said that “we may find clues about the meaning of a signal in its form”. We now ask, what does the form of proof-of-work tell us about its meaning? We also ask the difference between proof-of-work and spent satoshis, which can also be proven in a Bitcoin transaction.
What is the form of proof-of-work? An ASIC mining machine is very good at spending energy and proving that it has done so. An ideal cryptographic hash function cannot be inverted other than by trial-and-error and acts like a random number generator. The use of the hash function means that a distant observer will conclude that no trick could have been used and nothing useful was accomplished. Thus the form of proof-of-work is spent energy.
Nothing I know of is more real than energy. It is everywhere and everything. Matter and motion are forms of it. Furthermore, a rational mind and the scientific method is required to know thin. Energy is the abstract substance and someone who knows how to transform it knows about the fundamental nature of the universe. Thus, I see spent energy as opposing life, reason, and productivity. This is what proof-of-work means. It is antlers for rational animals.
Spent energy is not the same thing as spent satoshis. It is possible to demonstrate that satoshis have been spent but people will not, in general, agree on what opportunity cost has been demonstrated. The value of money is speculative and depends on all goods that exist now and in the future. It would be necessary to understand the whole economy in order to understand the cost of money. On the other hand, spending energy opposes all motion and thus all life and all technology immediately. Spending satoshis to promote content is not prima facie evidence that the promoter did not get those satoshis back in some backdoor deal. With Boost it is self-evident that the party incurred the cost and no collusion could have happened. Thus, spent satoshis are not a verifiable opportunity cost whereas proof-of-work is.
I designed Boost POW because I saw that the Bitcoin community was not immune to BTC Core ideas despite the fact that they are against any possibility of Bitcoin’s success. Core supporters were able to infect the Bitcoin community with their ideas by taking over forums like BitcoinTalk and /r/bitcoin. I did not believe that Core ideas were a threat in 2014 because anyone with a rudimentary understanding of Bitcoin would know that BitcoinTalk and /r/bitcoin were just the kind of trusted systems that Bitcoin had made obsolete and they did not rely on proof-of-work to filter information.
However, all honest actors were driven out and prevented from communicating with one another for a while due to being scattered and not knowing who each other was. This attack would be impossible if reddit was using the system I have designed because honest actors would be capable of increasing difficulty beyond that which dishonest actors could afford and thus retain the highest levels of attention from all participants. This was not possible on reddit because the reddit upvote system is not a genuine costly signal and therefore does not prevent manipulation. If people were actually treating proof-of-work as a signal of important information, the Bitcoin cash split would not have happened. There would have been big blocks on BTC.
Unfortunately, I did not know enough to be able to build an alternate system just then. Fortunately the people at Twetch have figured it out and done it. Boost POW will soon become an integral part of Twetch and is the last element required for Twetch to be competitive with reddit and all previous social networks. At that point, Twetch will become objectively stupid not join. Ideas on Twetch will be better due to the need for all participants to conserve energy as they communicate.
Of course, Boost is not only for Twetch. Boost is an upvote system that works independently of Twetch. Twetch is simply the among the first to incorporate it.
I gave a talk this year at Anarchapulco called “Bitcoin Needs to Get a Job” in which I discussed the need for the Bitcoin economy to be productive and to provide services for people if it is to be sustainable. With the Boost POW protocol, I have given Bitcoin a job. Boost is a new source of income for all miners and no one else can come close to competing with it.
Furthermore, everyone needs it. Everyone needs it because everyone is currently using systems that can be manipulated, just as we have seen happen with /r/bitcoin. As I said in my video “Investors are Powerful!”, you can change the world just by thinking. With the design of Boost POW, I have made the Bitcoin economy more viable.
In The Fountainhead, Ayn Rand said:
“Why wouldn't you like to see a human body with a curling tail with a crest of ostrich feathers at the end? And with ears shaped like acanthus leaves? It would be ornamental, you know, instead of the stark, bare ugliness we have now. Well, why don't you like the idea? Because it would be useless and pointless. Because the beauty of the human body is that it hasn't a single muscle which doesn't serve its purpose.”[^6]
Ayn Rand was wrong. Humans are better with antlers.
[^1]: Satoshi, “Bitcoin: A Peer-to-Peer Electronic Cash System”.
[^2]: Adam Back, "Hashcash - Amortizable Publicly Auditable Cost-Functions".
[^3]: Adam Back, “HashCash: A Denial of Service Countermeasure.”, Tech Report, Aug 2002.
[^4]: Zahavi, The Handicap Principle: A Missing Piece of Darwin's Puzzle, Oxford University Press USA, 1999.
[^5]: Graffen, “Biological Signals as Handicaps,” Journal of Theoretical Biology, Volume 144, Issue 4, 21 June 1990, Pages 517-546.
[^6]: Ayn Rand, The Fountainhead, Plume, 1994.