cryptography professor, founder&chief scientist, blockchain enthusiast, cryptographer by heart
Blockchain is a decentralisation revolution with the potential to change not only payment activities, but also decisions in future organisations to finance projects (aka ICOs), govern decentralized enterprises (aka DAOs) or curate lists (aka TCRs). A central tool of decision making is voting which can be seen as a consensus protocol with additional privacy guarantees. We argue that the standard democratic voting mechanism — one voter casts one vote — is vulnerable and fails to meet the requirements of contemporary blockchain applications. We present a radically new mechanism, called Knowledge Extractable Voting, that is impossible in the real world (dystopia), but it can be implemented in the blockchain world (cryptopia). We showcase the versatility and practicability in the case of decentralized autonomous decision making.
Voting is the crucial foundation that allowed most current societies and institutions succeed through giving members voice. It is the general mechanism for implementing democratic decisions and expressing opinion used not only for electing public officials, but also selecting decisions within a company. Even in the world of blockchain a voting comes in the game to facilitate consensus on the next block state, such as in a Proof of Stake , or to implement executive decisions as in the case of Decentralized Autonomous Organizations (DAOs).
There are different voting schemes used worldwide, yet the most popular ones are based on the one-person-one-vote principle. This is the democratic way as it captures the power of each individual voter. Such system has worked well in the past especially for North America and Europe. It made sure that candidates and decisions were judged on merit basis instead of the wealth or influence of a certain group.
However familiar, this voting scheme was not used always. Voting has been constantly changing and evolving. Some systems gave the voice to the masses, others only to privileged few. For instance, in ancient Rome only wealthy men who had proper heritage and owned property could vote while the voices of slaves, women, and the poor were never heard.
Our democratic voting scheme has come a long way from the disturbing Roman elitist system. However, such success does not necessarily mean that it is the end of its evolution. Recent history has shown that the current established voting systems are imperfect and can be exploited fairly easily.
Brexit and the 2017 U.S. Presidential Elections are great examples of how an individual’s lack of accountability, third-party tampering, and populist movements can have devastating consequences.
Now, more than ever, we realize that the voting system we all came to know and love is not perfect. It has shown to be ineffective in the context of governmental elections and can be even more flawed when applied to (decentralized) corporate decisions. The fundamental assumption democratic voting systems are based upon is that every voter is aware of his power, responsibility and makes rational choices. That is, voters base their choice on facts, analyze the information, and make their own independent decision. A voting scheme is a mechanism, and like any mechanism, it is susceptible to attack with the aim to drift voters away from the rational choice. For example, the increasing wave of populism — a contemporary form of attack — clouded the judgment of British voters with many regretting their choice after the election. The 2017 U.S. elections have been attacked by fake news — a new form of propaganda — biasing the information base of American voters.
Blockchain is a revolution and stands for liberation and radical decentralization of the information society. Thanks to the vehicle of smart contracts blockchain technologies come with a series of radically new concepts like Decentralized Autonomous Organizations, where people in the spirit of network nodes are permissionless, operate autonomously and perform based on a hard-coded decision mechanism known as consensus. Voting schemes are of crucial relevance to implement the consensus mechanism. They implement the liberal and democratic choice. Much care must therefore be taken to implement a robust mechanism against any form of attack in the same vein as Internet security protocols withstand cyberattacks. Otherwise democratic decentralized governance stays in Utopia! And will never reach Cryptopia — the ultimate place where distributed governance is celebrated!
The one-voter-one-vote scheme is not a universal mechanism to distributed governance. Rather it must be considered as one-out-of-many mechanisms in a protocol framework for decentralized blockchain applications. Hence much care must be taken when deploying the protocol for democratic decisions.
The idea of knowledge extractable voting is based on the assumption that wealth is unequally distributed — a fact today in the real world. It’s also based on the assumption that wealthy and rich people do not make choices in favor of the society, but rather rational choices in order to maximize their utility. Quoting Vitalik Buterin and Glen Weyl from their recent post on Liberation through Radical Decentralization:
After all, a system that formalizes only capital and not human individuality may inexorably serve wealth rather than humanity.
The canonical example is the industrial revolution, showcasing the conflict between employers interested in productivity/revenue and employees having been brutally exploited to this end. Basing a decision mechanism purely on wealth (expressed in tokens) is limiting, as it might rule out voters that have the desired expertise, but cannot afford the participation.
A radically new idea was proposed by Steven Lalley and Glen Weyl to mitigate the problem of unfair wealth distribution. The authors put forth the beautiful notion of Quadratic Voting (QV). Their idea is based on buying votes. A bit more precise, each voter can buy as many votes he wishes by paying the tokens in a fund with one caveat. The voter has to pay quadratically in the number of votes. The money is then returned to voters on a per capita basis. Suppose, for example, a voter intends to cast 10 votes. Then he pays 10^2=100 tokens to acquire the votes. On a high level, the quadratic pricing function acts like a wealth slow down mechanism. Lalley and Weyl have proven under certain assumptions QV to be a mechanism against a tyranny of majority stake holders.
While their results apply to real-world decision makings, transferring the scheme to the permission-less blockchain setting does not carry over with the expected outcome. The problem with the blockchain world are sybil attacks. The design of blockchain technologies allows a voter to cast many anonymous identities. Hence, to accumulate 10 votes, the sybil attacker simply creates 10 accounts under different identities. This way, the attacker requires 10 tokens in total to cast 10 votes. However, we would like to stress that QV may satisfy the desired outcome in the case of permission-based settings where the identities of the players are known and fixed in advance throughout the lifetime of the system(For example a proof of authority based system).
Inspired by the radically new and brilliant ideas behind QV, we present a scheme basing decisions on something we believe is sparse and better suited for blockchain applications — namely knowledge — to achieve a decision (partially) independent of wealth.
The beauty of our proposal derives from the fact that blockchains empower the tokenization of knowledge.
2.2.1 Design Goals
Every voter should be given a voice. This mechanism should not be based on what position one holds, their wealth/stake, skin color, or gender. Further, the mechanism should not discriminate, but instead incentivize voters to do a solicit analysis before making an important decision. Further the mechanism should reflect the values, norms, and ideas of a community. A community typically shares intent, belief, needs and risks in common affecting the identity of the participants and their degree of cohesiveness. The blockchain community shares, for example, the belief in and needs for decentralization. What makes a community unique is their knowledge in a particular domain.
As opposed to wealth knowledge is acquired through experience or education by perceiving, discovering, or learning. It can’t be bought on an exchange. It can’t be transferred from a knowledgable to less-knowledgable or wealthy person. Moreover, knowledge is non-fungible, as knowledge relates to a particular field of interest and expertise.
2.2.2 The Knowledge Extractable Voting
The novelty of our mechanism is to leverage a two-token model. The first, called ETH, is a staking token. The second, called KNW (for knowledge), is a non-fungible token.
Protocol Goal: Make a decision (e.g., is this a good new block).
Protocol Assumption: ETH tokens are fungible and tradable. They can be exchanged and transferred. KNW are non-fungible and non-tradable. Further they are non-transferable because they are linked to a particular ETH wallet address. (This captures the intuition of knowledge from the above discussion.)
Protocol Setup: All players in the network are in possession of ETH tokens. Suppose for ease of exposition that each players owns KNW tokens as well.
Protocol: The protocol runs between Alice who acts as a proposer and a set of community members, abbreviated as the voters, in the following way:
It remains to answer to what quantity the reward and punishment in terms of minting and burning KNW occurs. While the concrete parameterisation requires more research, we suggest the following lower and upper bounds:
The rationality behind the square root (i.e. inverse quadratic function) burn rate is to prevent wealthy voters from gaining KNW tokens simply through repetitive participation in the votings. Note, a wealthy voter may not fear to loose ETH token stakes or game the perceptual outcome of the decision by colluding with many voters.
2.3 Utility Function
Until now, we described the mechanics of the knowledge extractable voting scheme. It remains to utilize the gained knowledge in order to improve the voting outcome. We make three proposals:
Knowledge extractable voting has applications in Proof-of-Stake based protocols (PoS). PoS is a type of protocol through which consensus can be reached in a distributed system. Ethereum is planning to use PoS for fairly determining the creator of the next block of the blockchain; however, there are numerous other uses for this algorithm to resolve different issues in decentralized enterprises.
In PoS disputes are resolved by validators. They are individuals who are willing and able to stake (lock up) some of their coins (ETH) or tokens as a collateral on the outcome of the dispute. When the dispute gets resolved, those who bet on the right outcome are rewarded proportional to their initial stake. While this protocol is a huge improvement over Proof-of-Work (which can require up to several thousand times more electricity resources over a lifetime of a system), there is still room for improvement. The current problem with PoS is that is tailored towards giving significant stake holders the ability to frequently participate in the protocol and obtain rewards. As wealth is unequally distributed, it leaves the majority of decisions to the minority of rich stake holders.
The knowledge tokens can be used to improve the staking mechanism in PoS distributed systems by rewarding those who take their role as a validator seriously and base their bets on knowledge instead of making a pure guess. It can also be set up to punish those who do not put any thought in the staking and betting process. Suppose, for example, that the selection of the block proposer happens on a mix of ETH and KNW tokens. This way, knowledge balances out wealth, and gives also the non-wealthy participants to engage in the consensus.
Therefore, KNW tokens provide an incentive system that promotes transparency and educated decisions. It is an essential piece that may improve the PoS algorithm even further resulting in a more reliable and efficient way to resolve conflict in decentralized enterprises.
Graded or any form of token-curated registries (TCRs) is basically a list curated in a distributed way (i.e. without a central authority like google or amazon). Crypto-economic incentive mechanisms ensure that the owner of this list curates the content meticulously. TCR’s may be used for many things, such as: whitelisting websites, decentralized community-based map with points of interest, providing advertisers with websites most relevant for their content and many more. In simplest terms, they are basically community-vetted lists made of objects.
Knowledge extractable voting makes TCR’s to be even more accurate. In today’s world, an object within a TCR’s can still be compromised. A majority of people who did not have accurate knowledge on whether an object should truly be in the list (registry) could overpower several experts by pure chance. However, now with the KNW mechanisms, the probability of such scenario drops significantly. The system can make sure that there is a proportional distribution of experts, those who performed averagely, and those who performed poorly in the past voting rounds (represented in the green shaded area in the diagram above). This way token-curated lists effectively turn into knowledge-curated lists and have the advantage that for certain questions only the qualified people participate in the curation of the content.
It should be of utmost relevance for the community to take insights from the past elections into account for the design of decentralized, democratic blockchain applications (eg. DAO, DAICO, etc.). There is definitely room for improvement. The one-voter-one-vote scheme may not be the right process in crucial decisions that decrentralized blockchain project face. A similar argument may apply to schemes that purely rely on the wealth of the voters. The radically new approach to mitigate the defects of plain staking protocols (like in the case of proof of stake consensus) is to incorporate a second quantity next to wealth, namely knowledge. Everyone should be given a voice, yet there also should be some kind of mechanism that rewards individuals with experience who consistently make the right choice. This mechanism would not be based on what position one holds, their stake, skin color, or gender. It would not discriminate, but instead incentivize voters to do their homework before making an important decision.
The ideas behind knowledge extractable voting are clearly inspired by the work of Steven Lalley and Glen Weyl on Quadratic Voting and their Radical Markets theories. In fact their work paved the ground for seminal concepts underlying the weeve network protocol, and helped us to understand that classical one-voter-one-vote schemes are limited candidates in order to design graded token-curated device registries and marketplaces. Joint work with Sidd Bhasin and Vlad Cherevkov.
Knowledge extraction is a property of proof systems like ZK-SNARKs, dating back to the celebrated work of Goldwasser-Micali-Rackoff on Proofs of Knowledge and their formal treatment due to Bellare and Goldreich. Loosely speaking, a knowledge extractor captures the intuition that from the protocol execution one can learn the knowledge of the prover. That’s exactly the witness that distinguishes the prover (who “knows” the proof witness) from all other, potentially cheating players (who do not “know” the witness). In our mechanism design the winning players extract knowledge from the vote that distinguishes them from players deviating from the quorum.