Poseidon Hash Function implementation in Solidity
Currently, the most widely-used Poseidon hash function for EVM is implemented in JS, and it is performant but it could be more unreadable. Also, if you write a smart contract in Solidity, it has to link the bytecode or call an external contract address for hash functions, which is inconvenient.
In the future, Poseidon hash might be implemented as a precompile contract in the Ethereum protocol (https://eips.ethereum.org/EIPS/eip-5988), so that people can call it with cheap gas. However, I think it would still be valuable to have a Poseidon Solidity implementation as a baseline for the performance benchmark.
make sure that your noder version is >= 16.
npm install poseidon-sol
put the 2 elements that you want to hash into the array:
poseidon.hash([0, 0])
make sure to run the test and lint before making a PR.
npm installnpx hardhat test
you can see the test coverage by the following command:
npx hardhat coverage
npm installnpx solhint contracts/Poseidon.sol
npx hardhat compile: compile the contract