rusk-abi 0.7.0

// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
//
// Copyright (c) DUSK NETWORK. All rights reserved.

extern crate alloc;

use alloc::vec::Vec;
use canonical::{Canon, CanonError, Source};
use dusk_abi::{ContractId, HostModule, Query, ReturnValue};
use dusk_bls12_381::BlsScalar;
use dusk_bls12_381_sign::{
    PublicKey as BlsPublicKey, Signature as BlsSignature,
    APK as AggregatedBlsPublicKey,
};
use dusk_bytes::{DeserializableSlice, Serializable};
use dusk_pki::PublicKey;
use dusk_plonk::circuit;
use dusk_plonk::prelude::*;
use dusk_schnorr::Signature;

use crate::hash::Hasher;
use crate::{PublicInput, RuskModule, TRANSCRIPT_LABEL};

/// Hashes a vector of [`BlsScalar`] using Poseidon's sponge function
pub fn poseidon_hash(scalars: &[BlsScalar]) -> BlsScalar {
    dusk_poseidon::sponge::hash(scalars)
}

pub fn contract_to_scalar(address: &ContractId) -> BlsScalar {
    // TODO provisory fn until native ContractId -> BlsScalar conversion is
    // implemented
    // https://github.com/dusk-network/cargo-bake/issues/1
    let mut bls_address = [0u8; 32];

    bls_address.copy_from_slice(address.as_bytes());

    // Infallible conversion
    BlsScalar::from_bytes(&bls_address).unwrap_or_default()
}

/// Generate a [`ContractId`] address from the given slice of bytes, that is
/// also a valid [`BlsScalar`]
pub fn gen_contract_id(bytes: &[u8]) -> ContractId {
    let mut hasher = Hasher::new();
    hasher.update(bytes);
    ContractId::from_raw(hasher.output())
}

pub fn verify_proof(
    pp: &PublicParameters,
    proof: &[u8],
    vd: &[u8],
    pi: Vec<PublicInput>,
) -> Result<bool, CanonError> {
    let proof =
        Proof::from_slice(proof).map_err(|_| CanonError::InvalidEncoding)?;

    let verifier_data = VerifierData::from_slice(vd)
        .map_err(|_| CanonError::InvalidEncoding)?;

    let pi: Vec<PublicInputValue> =
        pi.into_iter().map(|pi| pi.into()).collect();

    Ok(circuit::verify(
        pp,
        &verifier_data,
        &proof,
        pi.as_slice(),
        TRANSCRIPT_LABEL,
    )
    .is_ok())
}

impl RuskModule {
    pub fn new(pp: &'static PublicParameters) -> Self {
        RuskModule { pp }
    }
}

impl HostModule for RuskModule {
    fn execute(&self, query: Query) -> Result<ReturnValue, CanonError> {
        let mut source = Source::new(query.as_bytes());

        let qid = u8::decode(&mut source)?;

        match qid {
            Self::POSEIDON_HASH => {
                let scalars = Vec::<BlsScalar>::decode(&mut source)?;
                let ret = poseidon_hash(&scalars);

                Ok(ReturnValue::from_canon(&ret))
            }

            Self::VERIFY_PROOF => {
                let proof = Vec::<u8>::decode(&mut source)?;
                let vd = Vec::<u8>::decode(&mut source)?;
                let pi = Vec::<PublicInput>::decode(&mut source)?;

                let ret = verify_proof(self.pp, &proof, &vd, pi)?;

                Ok(ReturnValue::from_canon(&ret))
            }

            Self::VERIFY_SCHNORR_SIGN => {
                let sign = Signature::decode(&mut source)?;
                let pk = PublicKey::decode(&mut source)?;
                let message = BlsScalar::decode(&mut source)?;
                let ret = sign.verify(&pk, message);

                Ok(ReturnValue::from_canon(&ret))
            }

            Self::VERIFY_BLS_SIGN => {
                let sign = BlsSignature::decode(&mut source)?;
                let pk = BlsPublicKey::decode(&mut source)?;
                let pk = AggregatedBlsPublicKey::from(&pk);
                let message = Vec::<u8>::decode(&mut source)?;
                let ret = pk.verify(&sign, message.as_slice()).is_ok();

                Ok(ReturnValue::from_canon(&ret))
            }

            _ => todo!(),
        }
    }
}