Official way to transform the UInt8Array output of Poseidon into a BigInt? about circomlibjs HOT 7 CLOSED

Hello @bmdelacruz,
I finally managed to solve my issue (using PedersenHash), te solution was to use a mix of utils.leBuf2Int, utils.leInt2Buf and stringifyBigInts depending on the input the functions were expecting.
Hope you can manage to solve yours

from circomlibjs.

I found one which can be used without ffjavascript. someLEBufferToBigIntFunction can be ffjavascript.utils.leBuff2int but it's easy to write it by yourself.

const expectedBigInt = someLEBufferToBigIntFunction(
  poseidon.F.fromMontgomery(poseidon([/* some input */]))
)

from circomlibjs.

@manueljishi Thank you very much!

from circomlibjs.

Hello there,
same issue here.
Could you explain your methos a little more? Where does that string come from?
Thank you very much

from circomlibjs.

Sorry @manueljishi but I have no logical explanation for that code.

I was trying to recreate the normalize call at the end of the poseidon function in v0.0.8. But since poseidon.F does not have a normalize function, I tried to recreate the BN128 curve using the ZqField class which has a normalize function. I was very disappointed when I called ZqField.normalize because I got an error–it needs a BigInt input. Out of frustration, I tried the functions under the ZqField class that does not look like a math operation and stumbled upon fromRprLEM. 😅

That string is the prime for the bn128 curve and it probably came from here.

from circomlibjs.

@manueljishi, just for a reference in the future, how do you use pedersenHash.hash and transform its output to bigint?

I tried using it out of curiousity but I can't seem to get the same value the circuit produces. I also tried passing its output to pedersenHash.babyJub.unpackPoint but none of its outputs matched what I expected.

Your response would be very much appreciated.

from circomlibjs.

@bmdelacruz I am using JavaScript to test my circuits, this is how I am parsing all the data https://github.com/Elpacos/Zk_voting_system/blob/main/test/generate_circuit_witness.js
Hope this helps you

from circomlibjs.