poseidon_bug: A TypeScript repository from weijiekoh

There seems to be a bug with the Poseidon hash function bytecode generator in circomlib 0.0.20.

To demonstrate this bug, clone this repository, install dependencies, and compile the source code:

git clone https://github.com/weijiekoh/poseidon_bug.git && \
cd poseidon_bug && \
npm i && npm run build

In a separate terminal, run:

npm run ganache

Next, run:

node build/index.js

If the output is:

21334876322667183667165053088102559857160636052568525182000620475434027971580
21334876322667183667165053088102559857160636052568525182000620475434027971580

then there is a bug with the Poseidon hash contract bytecode generator.

The bug occurs when the t value is set to anything other than 6:

poseidonGenContract.createCode(3, 8, 57, POSEIDON_SEED)

It returns the same value for any input, which should not be the case.

If set to 6, the contract's poseidon() function will return different hash values for different inputs.