This repository contains an implementation of the Poseidon hash function, based on the Poseidon paper. The circuit is optimized for use with the BLS12-381 elliptic curve, and the constants are generated using the official Poseidon implementation, ensuring a security level of 128 bits.
The paper provides an appendix with a more efficient implementation. This current version is an initial iteration, and incorporating the optimized approach from the appendix could further reduce the number of constraints.
You can add the circuit to your project using the npm package manager:
$ npm install poseidon-bls12381-circom
Alternatively, you can manually copy the files from the circuits
folder into your project. Once the files are in place, you can include them in your Circom circuit as follows:
include "./node_modules/poseidon-bls12381-circom/circuits/poseidon255.circom";
To instantiate the main template with a specific arity, use this example:
pragma circom 2.0.0;
include "./node_modules/poseidon-bls12381-circom/circuits/poseidon255.circom";
component main = Poseidon255(2);
You can also use the TypeScript version of Poseidon for BLS12-381 if needed.