snarkvm-algorithms 0.4.0

Algorithms for a decentralized virtual machine
Documentation 
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// Copyright (C) 2019-2021 Aleo Systems Inc.
// This file is part of the snarkVM library.

// The snarkVM library is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// The snarkVM library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with the snarkVM library. If not, see <https://www.gnu.org/licenses/>.

use snarkvm_curves::Group;

use super::{PedersenCRHParameters, PedersenSize};

pub const BOWE_HOPWOOD_CHUNK_SIZE: usize = 3;
pub const BOWE_HOPWOOD_LOOKUP_SIZE: usize = 2usize.pow(BOWE_HOPWOOD_CHUNK_SIZE as u32);

#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
pub struct BoweHopwoodPedersenCRHParameters<G: Group> {
    pub base_lookup: Vec<Vec<[G; BOWE_HOPWOOD_LOOKUP_SIZE]>>,
}

impl<G: Group> BoweHopwoodPedersenCRHParameters<G> {
    pub fn setup<S: PedersenSize>(input: &PedersenCRHParameters<G, S>) -> Self {
        Self {
            base_lookup: input
                .bases
                .iter()
                .map(|x| {
                    x.iter()
                        .map(|g| {
                            let mut out = [G::zero(); BOWE_HOPWOOD_LOOKUP_SIZE];
                            for i in 0..BOWE_HOPWOOD_LOOKUP_SIZE {
                                let mut encoded = *g;
                                if (i & 0x01) != 0 {
                                    encoded += g;
                                }
                                if (i & 0x02) != 0 {
                                    encoded += &g.double();
                                }
                                if (i & 0x04) != 0 {
                                    encoded = encoded.neg();
                                }
                                out[i] = encoded;
                            }
                            out
                        })
                        .collect()
                })
                .collect(),
        }
    }
}