snarkvm_circuit_algorithms/poseidon/
hash_to_scalar.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
16use super::*;
17
18impl<E: Environment, const RATE: usize> HashToScalar for Poseidon<E, RATE> {
19    type Input = Field<E>;
20    type Scalar = Scalar<E>;
21
22    /// Returns a scalar from hashing the input.
23    /// This method uses truncation (up to data bits) to project onto the scalar field.
24    #[inline]
25    fn hash_to_scalar(&self, input: &[Self::Input]) -> Self::Scalar {
26        // Hash the input to the base field.
27        let output = self.hash(input);
28        // Convert the output to the scalar field,
29        // truncating to the size in data bits (1 bit less than the MODULUS) of the scalar.
30        Scalar::from_field_lossy(&output)
31    }
32}
33
34#[cfg(all(test, feature = "console"))]
35mod tests {
36    use super::*;
37    use snarkvm_circuit_types::environment::Circuit;
38
39    use anyhow::Result;
40
41    const DOMAIN: &str = "PoseidonCircuit0";
42    const ITERATIONS: usize = 10;
43    const RATE: usize = 4;
44
45    fn check_hash_to_scalar(
46        mode: Mode,
47        num_inputs: usize,
48        num_constants: u64,
49        num_public: u64,
50        num_private: u64,
51        num_constraints: u64,
52        rng: &mut TestRng,
53    ) -> Result<()> {
54        use console::HashToScalar as H;
55
56        let native = console::Poseidon::<<Circuit as Environment>::Network, RATE>::setup(DOMAIN)?;
57        let poseidon = Poseidon::<Circuit, RATE>::constant(native.clone());
58
59        for i in 0..ITERATIONS {
60            // Prepare the preimage.
61            let native_input = (0..num_inputs).map(|_| Uniform::rand(rng)).collect::<Vec<_>>();
62            let input = native_input.iter().map(|v| Field::<Circuit>::new(mode, *v)).collect::<Vec<_>>();
63
64            // Compute the native hash to scalar.
65            let expected = native.hash_to_scalar(&native_input)?;
66
67            // Compute the circuit hash.
68            Circuit::scope(format!("Poseidon {mode} {i}"), || {
69                let candidate = poseidon.hash_to_scalar(&input);
70                assert_eq!(expected, candidate.eject_value());
71                let case = format!("(mode = {mode}, num_inputs = {num_inputs})");
72                assert_scope!(case, num_constants, num_public, num_private, num_constraints);
73            });
74            Circuit::reset();
75        }
76        Ok(())
77    }
78
79    #[test]
80    fn test_hash_to_scalar_constant() -> Result<()> {
81        let mut rng = TestRng::default();
82
83        for num_inputs in 0..=RATE {
84            check_hash_to_scalar(Mode::Constant, num_inputs, 254, 0, 0, 0, &mut rng)?;
85        }
86        Ok(())
87    }
88
89    #[test]
90    fn test_hash_to_scalar_public() -> Result<()> {
91        let mut rng = TestRng::default();
92
93        check_hash_to_scalar(Mode::Public, 0, 254, 0, 0, 0, &mut rng)?;
94        check_hash_to_scalar(Mode::Public, 1, 1, 0, 840, 842, &mut rng)?;
95        check_hash_to_scalar(Mode::Public, 2, 1, 0, 845, 847, &mut rng)?;
96        check_hash_to_scalar(Mode::Public, 3, 1, 0, 850, 852, &mut rng)?;
97        check_hash_to_scalar(Mode::Public, 4, 1, 0, 855, 857, &mut rng)?;
98        check_hash_to_scalar(Mode::Public, 5, 1, 0, 1210, 1212, &mut rng)?;
99        check_hash_to_scalar(Mode::Public, 6, 1, 0, 1210, 1212, &mut rng)?;
100        check_hash_to_scalar(Mode::Public, 7, 1, 0, 1210, 1212, &mut rng)?;
101        check_hash_to_scalar(Mode::Public, 8, 1, 0, 1210, 1212, &mut rng)?;
102        check_hash_to_scalar(Mode::Public, 9, 1, 0, 1565, 1567, &mut rng)?;
103        check_hash_to_scalar(Mode::Public, 10, 1, 0, 1565, 1567, &mut rng)
104    }
105
106    #[test]
107    fn test_hash_to_scalar_private() -> Result<()> {
108        let mut rng = TestRng::default();
109
110        check_hash_to_scalar(Mode::Private, 0, 254, 0, 0, 0, &mut rng)?;
111        check_hash_to_scalar(Mode::Private, 1, 1, 0, 840, 842, &mut rng)?;
112        check_hash_to_scalar(Mode::Private, 2, 1, 0, 845, 847, &mut rng)?;
113        check_hash_to_scalar(Mode::Private, 3, 1, 0, 850, 852, &mut rng)?;
114        check_hash_to_scalar(Mode::Private, 4, 1, 0, 855, 857, &mut rng)?;
115        check_hash_to_scalar(Mode::Private, 5, 1, 0, 1210, 1212, &mut rng)?;
116        check_hash_to_scalar(Mode::Private, 6, 1, 0, 1210, 1212, &mut rng)?;
117        check_hash_to_scalar(Mode::Private, 7, 1, 0, 1210, 1212, &mut rng)?;
118        check_hash_to_scalar(Mode::Private, 8, 1, 0, 1210, 1212, &mut rng)?;
119        check_hash_to_scalar(Mode::Private, 9, 1, 0, 1565, 1567, &mut rng)?;
120        check_hash_to_scalar(Mode::Private, 10, 1, 0, 1565, 1567, &mut rng)
121    }
122}
snarkvm_circuit_algorithms/poseidon/hash_to_scalar.rs

snarkvm_circuit_algorithms/poseidon/
hash_to_scalar.rs
