Awesome
@waku/rln
This browser library enables the usage of RLN with Waku, as specified in the Waku v2 RLN Relay RFC.
Purpose
RLN Cryptography
The RLN cryptographic function are provided by zerokit.
This is imported via the @waku/zerokit-rln-wasm
dependencies which contains a WASM extract of zerokit's RLN functions.
Note that RLN Credentials generated with zerokit
, and hence @waku/rln
, are compatible with semaphore credentials.
Note that the WASM blob uses browser APIs, NodeJS is not supported.
Waku Interfaces
This library implements the IEncoder
and IDecoder
interfaces of js-waku.
This enables a seamless usage with js-waku applications, as demonstrated in the rln-js example.
Comparison to Existing Work
Rate-Limiting-Nullifier/rlnjs is an existing JavaScript / TypeScript library that already provides RLN cryptographic functionalities for the browser.
The core difference is that @waku/rln
uses zerokit for cryptography and provide opinionated interfaces to use RLN specifically in the context of Waku.
Install
npm install @waku/rln
# or with yarn
yarn add @waku/rln
Or to use ESM import directly from a <script>
tag:
<script type="module">
import * as rln from "https://unpkg.com/@waku/rln@0.0.13/bundle/index.js";
</script>
Running example app
git clone https://github.com/waku-org/js-rln
cd js-rln/
npm install
cd example/
npm install # or yarn
npm start
Browse http://localhost:8080 and open the dev tools console to see the proof being generated and its verification
Usage
Initializing the Library
import * as rln from "@waku/rln";
const rlnInstance = await rln.createRLN();
Starting RLN to listen to a contract
import * as rln from "@waku/rln";
const rlnInstance = await rln.createRLN();
await rlnInstance.start(); // will use default Sepolia contract
Generating RLN Membership Credentials
let credentials = rlnInstance.generateIdentityCredentials();
Generating RLN Membership Keypair Using a Seed
This can be used to generate credentials from a signature hash (e.g. signed by an Ethereum account).
let credentials = rlnInstance.generateSeededIdentityCredentials(seed);
Adding Membership Keys Into Merkle Tree
rlnInstance.insertMember(credentials.IDCommitment);
Registering Membership on a contract
import * as rln from "@waku/rln";
const rlnInstance = await rln.createRLN();
await rlnInstance.start(); // will use default Sepolia contract
const membershipInfo = await rlnInstance.contract.registerWithKey(credentials);
Generating a Proof
// prepare the message
const uint8Msg = Uint8Array.from(
"Hello World".split("").map((x) => x.charCodeAt())
);
// setting up the epoch (With 0s for the test)
const epoch = new Uint8Array(32);
// generating a proof
const proof = await rlnInstance.generateProof(
uint8Msg,
index,
epoch,
credentials.IDSecretHash
);
Verifying a Proof
try {
// verify the proof
const verificationResult = rlnInstance.verifyProof(proof, uint8Msg);
console.log("Is proof verified?", verificationResult ? "yes" : "no");
} catch (err) {
console.log("Invalid proof");
}
Updating Circuit, Verification Key and Zkey
The RLN specs defines the defaults.
These values are fixed and should not change.
Currently, these resources are being used.
If they change, this file needs to be updated in resources.ts
which
contains these values encoded in base64 in this format:
const verification_key = "...";
const circuit = "..."; // wasm file generated by circom
const zkey = "...";
export {verification_key, circuit, zkey};
A tool like GNU's base64
could be used to encode this data.
Updating Zerokit
- Make sure you have NodeJS installed and a C compiler
- Install wasm-pack
curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh
- Compile RLN for wasm
git clone https://github.com/vacp2p/zerokit
cd zerokit/rln-wasm
wasm-pack build --release
- Copy
pkg/rln*
intosrc/zerokit
Bugs, Questions & Features
If you encounter any bug or would like to propose new features, feel free to open an issue.
For more general discussion, help and latest news, join Vac Discord or Telegram.
License
Licensed and distributed under either of
- MIT license: LICENSE-MIT or http://opensource.org/licenses/MIT
or
- Apache License, Version 2.0, (LICENSE-APACHE-v2 or http://www.apache.org/licenses/LICENSE-2.0)
at your option. These files may not be copied, modified, or distributed except according to those terms.