snarkvm_console_algorithms/pedersen/
mod.rs

1// Copyright 2024 Aleo Network Foundation
2// This file is part of the snarkVM library.
3
4// Licensed under the Apache License, Version 2.0 (the "License");
5// you may not use this file except in compliance with the License.
6// You may obtain a copy of the License at:
7
8// http://www.apache.org/licenses/LICENSE-2.0
9
10// Unless required by applicable law or agreed to in writing, software
11// distributed under the License is distributed on an "AS IS" BASIS,
12// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13// See the License for the specific language governing permissions and
14// limitations under the License.
15
16mod commit;
17mod commit_uncompressed;
18mod hash;
19mod hash_uncompressed;
20
21use crate::Blake2Xs;
22use snarkvm_console_types::prelude::*;
23
24use std::{borrow::Cow, sync::Arc};
25
26/// Pedersen64 is an *additively-homomorphic* collision-resistant hash function that takes up to a 64-bit input.
27pub type Pedersen64<E> = Pedersen<E, 64>;
28/// Pedersen128 is an *additively-homomorphic* collision-resistant hash function that takes up to a 128-bit input.
29pub type Pedersen128<E> = Pedersen<E, 128>;
30
31/// Pedersen is a collision-resistant hash function that takes a variable-length input.
32/// The Pedersen hash function does *not* behave like a random oracle, see Poseidon for one.
33#[derive(Clone)]
34pub struct Pedersen<E: Environment, const NUM_BITS: u8> {
35    /// The base window for the Pedersen hash.
36    base_window: Arc<Vec<Group<E>>>,
37    /// The random base window for the Pedersen commitment.
38    random_base_window: Arc<Vec<Group<E>>>,
39}
40
41impl<E: Environment, const NUM_BITS: u8> Pedersen<E, NUM_BITS> {
42    /// Initializes a new instance of Pedersen with the given setup message.
43    pub fn setup(message: &str) -> Self {
44        // Construct an indexed message to attempt to sample a base.
45        let (generator, _, _) = Blake2Xs::hash_to_curve::<E::Affine>(&format!("Aleo.Pedersen.Base.{message}"));
46        // Construct the window with the base.
47        let mut base_window = vec![Group::<E>::zero(); NUM_BITS as usize];
48        {
49            let mut base_power = Group::<E>::new(generator);
50            for base in base_window.iter_mut().take(NUM_BITS as usize) {
51                *base = base_power;
52                base_power = base_power.double();
53            }
54            assert_eq!(base_window.len(), NUM_BITS as usize);
55        }
56
57        // Compute the random base.
58        let (generator, _, _) = Blake2Xs::hash_to_curve::<E::Affine>(&format!("Aleo.Pedersen.RandomBase.{message}"));
59        // Construct the window with the random base.
60        let mut random_base = Vec::with_capacity(Scalar::<E>::size_in_bits());
61        {
62            let mut base = Group::<E>::new(generator);
63            for _ in 0..Scalar::<E>::size_in_bits() {
64                random_base.push(base);
65                base = base.double();
66            }
67            assert_eq!(random_base.len(), Scalar::<E>::size_in_bits());
68        }
69
70        Self { base_window: Arc::new(base_window.to_vec()), random_base_window: Arc::new(random_base) }
71    }
72
73    /// Returns the base window.
74    pub fn base_window(&self) -> &Arc<Vec<Group<E>>> {
75        &self.base_window
76    }
77
78    /// Returns the random base window.
79    pub fn random_base_window(&self) -> &Arc<Vec<Group<E>>> {
80        &self.random_base_window
81    }
82}
snarkvm_console_algorithms/pedersen/mod.rs

snarkvm_console_algorithms/pedersen/
mod.rs
