1use std::{fmt::Debug, marker::PhantomData};
  2
  3use crate::crh::{
  4    FixedLengthCRHGadget,
  5    injective_map::{InjectiveMap, PedersenCRHCompressor, TECompressor},
  6    pedersen::{
  7        PedersenWindow,
  8        constraints::{PedersenCRHGadget, PedersenCRHGadgetParameters},
  9    }
 10};
 11
 12use algebra::{
 13    curves::{
 14        models::{ModelParameters, TEModelParameters},
 15        twisted_edwards_extended::{GroupAffine as TEAffine, GroupProjective as TEProjective},
 16    },
 17    fields::{Field, PrimeField, SquareRootField},
 18    groups::Group,
 19};
 20use r1cs_core::{ConstraintSystem, SynthesisError};
 21use r1cs_std::{
 22    fields::fp::FpGadget,
 23    groups::{curves::twisted_edwards::AffineGadget as TwistedEdwardsGadget, GroupGadget},
 24    prelude::*,
 25};
 26
 27pub trait InjectiveMapGadget<G: Group, I: InjectiveMap<G>, ConstraintF: Field, GG: GroupGadget<G, ConstraintF>> {
 28    type OutputGadget: EqGadget<ConstraintF>
 29        + ToBytesGadget<ConstraintF>
 30        + CondSelectGadget<ConstraintF>
 31        + AllocGadget<I::Output, ConstraintF>
 32        + Debug
 33        + Clone
 34        + Sized;
 35
 36    fn evaluate_map<CS: ConstraintSystem<ConstraintF>>(
 37        cs: CS,
 38        ge: &GG,
 39    ) -> Result<Self::OutputGadget, SynthesisError>;
 40}
 41
 42pub struct TECompressorGadget;
 43
 44impl<ConstraintF, P> InjectiveMapGadget<TEAffine<P>, TECompressor, ConstraintF, TwistedEdwardsGadget<P, ConstraintF, FpGadget<ConstraintF>>>
 45    for TECompressorGadget
 46where
 47    ConstraintF: PrimeField + SquareRootField,
 48    P: TEModelParameters + ModelParameters<BaseField = ConstraintF>,
 49{
 50    type OutputGadget = FpGadget<ConstraintF>;
 51
 52    fn evaluate_map<CS: ConstraintSystem<ConstraintF>>(
 53        _cs: CS,
 54        ge: &TwistedEdwardsGadget<P, ConstraintF, FpGadget<ConstraintF>>,
 55    ) -> Result<Self::OutputGadget, SynthesisError> {
 56        Ok(ge.x.clone())
 57    }
 58}
 59
 60impl<ConstraintF, P>
 61    InjectiveMapGadget<TEProjective<P>, TECompressor, ConstraintF, TwistedEdwardsGadget<P, ConstraintF, FpGadget<ConstraintF>>>
 62    for TECompressorGadget
 63where
 64    ConstraintF: PrimeField + SquareRootField,
 65    P: TEModelParameters + ModelParameters<BaseField = ConstraintF>,
 66{
 67    type OutputGadget = FpGadget<ConstraintF>;
 68
 69    fn evaluate_map<CS: ConstraintSystem<ConstraintF>>(
 70        _cs: CS,
 71        ge: &TwistedEdwardsGadget<P, ConstraintF, FpGadget<ConstraintF>>,
 72    ) -> Result<Self::OutputGadget, SynthesisError> {
 73        Ok(ge.x.clone())
 74    }
 75}
 76
 77pub struct PedersenCRHCompressorGadget<G, I, ConstraintF, GG, IG>
 78where
 79    G: Group,
 80    I: InjectiveMap<G>,
 81    ConstraintF: Field,
 82    GG: GroupGadget<G, ConstraintF>,
 83    IG: InjectiveMapGadget<G, I, ConstraintF, GG>,
 84{
 85    _compressor:        PhantomData<I>,
 86    _compressor_gadget: PhantomData<IG>,
 87    _crh:               PedersenCRHGadget<G, ConstraintF, GG>,
 88}
 89
 90impl<G, I, ConstraintF, GG, IG, W> FixedLengthCRHGadget<PedersenCRHCompressor<G, I, W>, ConstraintF>
 91    for PedersenCRHCompressorGadget<G, I, ConstraintF, GG, IG>
 92where
 93    G: Group,
 94    I: InjectiveMap<G>,
 95    ConstraintF: Field,
 96    GG: GroupGadget<G, ConstraintF>,
 97    IG: InjectiveMapGadget<G, I, ConstraintF, GG>,
 98    W: PedersenWindow,
 99{
100    type OutputGadget = IG::OutputGadget;
101    type ParametersGadget = PedersenCRHGadgetParameters<G, W, ConstraintF, GG>;
102
103    fn check_evaluation_gadget<CS: ConstraintSystem<ConstraintF>>(
104        mut cs: CS,
105        parameters: &Self::ParametersGadget,
106        input: &[UInt8],
107    ) -> Result<Self::OutputGadget, SynthesisError> {
108        let result = PedersenCRHGadget::<G, ConstraintF, GG>::check_evaluation_gadget(
109            cs.ns(|| "PedCRH"),
110            parameters,
111            input,
112        )?;
113        IG::evaluate_map(cs.ns(|| "InjectiveMap"), &result)
114    }
115}