Encointer is a very secure and decentralized sybil-defense protocol, but it has systemic limits to growth. The protocol is very involved as it demands not only physical appearance at regular cycle gatherings: it requires an active community in your vicinity in the first place, which means significant work and dedication of a group of people. Even if there is a community in your vicinity, the protocol can only tolerate bounded growth of a community’s population due to its security assumptions.
So, the question is: How can Encointer grow to a globally significant number of users in reasonable time?
Encointer today relies entirely on a presence-based sybil-resilience mechanism. One alternative approach (followed by BrightID) is to rely on a social graph where people vouch for each other. While such a protocol is much less secure than Encointer’s, it is a lot more accessible and can potentially grow virally. This post explores if a combination of the two approaches could yield the best of both worlds.
The Idea: Let reputables of Encointer communities vouch for persons they know or meet personally
We have no reason to trust reputables to honestly only vouch for real people and only for one of their accounts. Therefore, we might want to involve staking and slashing. Slashing could be invoked by a democratic process in a community based on evidence for double signing a person, or signing for sybils.
trust&connection levels
Similar to PGP key signing, vouching for someone should happen along trust levels. Stake alone is not a sufficient indicator of trust because - along the spirit of Encointer- the trust from a wealthy person should not have higher value than the trust from a poor person, at least not for every use case.
trust
- I trust this person to not claim vouches on other accounts too
- I don’t know this person well enough to vouch for her honesty
connection
- I verified this person’s account at a physical enounter
- I verified this person’s account and performed a turing test at a virtual encounter (videocall, audiocall)
Growth potential
If we only allow first-degree vouches (not allowing vouched non-reputables to vouch), the growth will stay linear, but still, the growth rate is unbounded
We could hold regular virtual video meetings open to everyone where reputables do quick turing tests with everyone before they vouch with the minimal trust level.
We could also use in-person events like conferences or meetups to offer vouches with higher trust levels to target groups
It might even become a business model for reputables to vouch for other people, similar to Polkadot registrar judgements
Use Cases
Many use cases exist that need a bounded sybil-resilience but don’t require the high security guarantees of the Encointer protocol. The concept of vouches alone, as presented here can not guarantee to bound sybil-attacks (the number of possible sybils). But, if combined with social graph analytics it may be sound for many cases.
Examples:
- reviews (i.e. for tripadvisor and the like)
- replacing CAPTCHAs
- social media badges (differenciated confidence levels that an account is owned by a real person)
- forums for Polkadot governance (like polkassembly, subsquare) where discussion sentiment should be protected from sockpuppet statements
Counter-examples: Such social vouches may not be suitable for
- quadratic or 1p1v voting
- UBI
deprecating “endorsements”
the current protocol allows reputables to endorse newbies to ensure they will be assigned to a cycle gathering. This entire process could be replaced by the proposed vouches