Ephemerant allows you to interact with people whose paths you've crossed.
It is a Zero-Knowledge primitive for connecting users in ephemeral cohorts based on common behaviour. It is anonymous, opt-in, and fully-decentralized.
In a way, it creates the basis for Gibson's version of Cyberspace, an interweaving set of ephemeral hubs that have no center, and can only be revealed to individual users as they decide on their own paths. (Prophetically, a theme in Neuromancer was moving communication fleetingly out of public spheres to avoid the gaze of AIs.)
When implemented in a website or app, users' paths are recorded (locally only) but as their paths weave and overlap with others, they're placed in an ephemeral cohort and can choose to engage with each other. (Anonymously by default.)
This mechanism is opt-in and zero knowledge, so the user can choose to join or not at any point. If they join, no personal information is needed, they simply share a common key with others on their path, an ephemerant key that represents each ephemeral cohort.
Each user's path is recorded on a separate "local" merkle tree, but verified and made consistent using a common on-chain tree root.
Paths are created through recursively-referenced Links objects, which each contain a URL and reference to the previous Link. (The URL can be substituted for any other data referencing a user event.) Those Paths are recorded off-chain with zk-SNARKS, and verified on-chain on the Mina Blockchain. Common areas for communication (created by the shared ephemerant key) are therefore completely generative. When Paths span internet locations hosted by different parties, they are even unpredictable and unknowable to hosts. Since the ephemerant keys are generated from these paths, they create spaces that only be found by users themselves.
This key can be used in many ways, for example to create a group chat, specify a secret meeting link, or expose an airdrop to visitors who find their way to the right pages on a site.
This might also be used to create a channel for multi-party key generation.
Broadly, this primitive opens new opportunities for social interaction, education, group coordination and access control - all without the need to share personal information.
With little modification, the definition of a matching path can be modified to:
- include a time window (e.g. 5 minutes, 1 month, etc.)
- a dynamic number of previous pages, optimising for cohorts with more in common or of specific sizes
contracts/src/Paths.ts produces 3 exports:
- Paths - a smart contract that verifies state of a Merkle Tree of Links
- Links - a struct that recursively tracks user actions
- friendsHash - a function that produces a unique hash given two Links. (This is the ephemerant key.)
contracts/src/Paths.test.ts contains the unit tests, which are set up based on the user scenario below
A real-world implementation could use an ephemerant key to connect users to an on-site chat (like customer-support interfaces, but making peer connections real-time), or link them to a common third-part room in Matrix chat, using that key.
The test in Paths.test.js runs based on a scenario of 5 users entering a website at different pages. If any two users visit the same page, and then click on the same link, they are given the same friendHash key (the ephemerant key).
They can meet others on the same path (defined as visiting the same page and the same previous pages)
A first user visits 3 pages, and is joined by one more on the way. And a third on the last page.
Since only the first 2 users share a common path (the third only joined for a single page) those two users are connected by revealing the same friendHash.
Two others arrive on a separate page, but are not considered on the same path, since a path requires 2 common pages.
The test file has comments, to allow you to follow along this scenario alongside the technical implementation.
- generalise the terminology: Links should be Action, friendHash should be EphemerantKey
- implement dynamic parameters (above)
- build a chat component that automatically connects users to cohort-mates
npm run buildnpm run test
npm run testw # watch modenpm run coverage