snarkvm_console_account/signature/
from_bits.rs

1// Copyright (c) 2019-2025 Provable Inc.
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<N: Network> FromBits for Signature<N> {
19    /// Initializes a new signature from a list of **little-endian** bits.
20    fn from_bits_le(bits_le: &[bool]) -> Result<Self> {
21        let scalar_size_in_bits = Scalar::<N>::size_in_bits();
22        let compute_key_size_in_bits = ComputeKey::<N>::size_in_bits();
23
24        let (challenge_start, challenge_end) = (0, scalar_size_in_bits);
25        let (response_start, response_end) = (challenge_end, challenge_end + scalar_size_in_bits);
26        let (compute_key_start, compute_key_end) = (response_end, response_end + compute_key_size_in_bits);
27
28        let Some(challenge_bits) = bits_le.get(challenge_start..challenge_end) else {
29            bail!("Unable to recover the signature challenge from (LE) bits");
30        };
31        let Some(response_bits) = bits_le.get(response_start..response_end) else {
32            bail!("Unable to recover the signature response from (LE) bits");
33        };
34        let Some(compute_key_bits) = bits_le.get(compute_key_start..compute_key_end) else {
35            bail!("Unable to recover the signature compute key from (LE) bits");
36        };
37
38        Ok(Self {
39            challenge: Scalar::from_bits_le(challenge_bits)?,
40            response: Scalar::from_bits_le(response_bits)?,
41            compute_key: ComputeKey::from_bits_le(compute_key_bits)?,
42        })
43    }
44
45    /// Initializes a new signature from a list of **big-endian** bits.
46    fn from_bits_be(bits_be: &[bool]) -> Result<Self> {
47        let scalar_size_in_bits = Scalar::<N>::size_in_bits();
48        let compute_key_size_in_bits = ComputeKey::<N>::size_in_bits();
49
50        let (challenge_start, challenge_end) = (0, scalar_size_in_bits);
51        let (response_start, response_end) = (challenge_end, challenge_end + scalar_size_in_bits);
52        let (compute_key_start, compute_key_end) = (response_end, response_end + compute_key_size_in_bits);
53
54        let Some(challenge_bits) = bits_be.get(challenge_start..challenge_end) else {
55            bail!("Unable to recover the signature challenge from (BE) bits");
56        };
57        let Some(response_bits) = bits_be.get(response_start..response_end) else {
58            bail!("Unable to recover the signature response from (BE) bits");
59        };
60        let Some(compute_key_bits) = bits_be.get(compute_key_start..compute_key_end) else {
61            bail!("Unable to recover the signature compute key from (BE) bits");
62        };
63
64        Ok(Self {
65            challenge: Scalar::from_bits_be(challenge_bits)?,
66            response: Scalar::from_bits_be(response_bits)?,
67            compute_key: ComputeKey::from_bits_be(compute_key_bits)?,
68        })
69    }
70}
71
72#[cfg(test)]
73mod tests {
74    use super::*;
75    use snarkvm_console_network::MainnetV0;
76
77    type CurrentNetwork = MainnetV0;
78
79    const ITERATIONS: usize = 100;
80
81    fn check_from_bits_le() -> Result<()> {
82        let rng = &mut TestRng::default();
83
84        for i in 0..ITERATIONS {
85            // Sample a random signature.
86            let expected = test_helpers::sample_signature(i as u64, rng);
87
88            let given_bits = expected.to_bits_le();
89            assert_eq!(Signature::<CurrentNetwork>::size_in_bits(), given_bits.len());
90
91            let candidate = Signature::<CurrentNetwork>::from_bits_le(&given_bits)?;
92            assert_eq!(expected, candidate);
93
94            // Add excess zero bits.
95            let candidate = [given_bits, vec![false; i]].concat();
96
97            let candidate = Signature::<CurrentNetwork>::from_bits_le(&candidate)?;
98            assert_eq!(expected, candidate);
99            assert_eq!(Signature::<CurrentNetwork>::size_in_bits(), candidate.to_bits_le().len());
100        }
101        Ok(())
102    }
103
104    fn check_from_bits_be() -> Result<()> {
105        let rng = &mut TestRng::default();
106
107        for i in 0..ITERATIONS {
108            // Sample a random signature.
109            let expected = test_helpers::sample_signature(i as u64, rng);
110
111            let given_bits = expected.to_bits_be();
112            assert_eq!(Signature::<CurrentNetwork>::size_in_bits(), given_bits.len());
113
114            let candidate = Signature::<CurrentNetwork>::from_bits_be(&given_bits)?;
115            assert_eq!(expected, candidate);
116
117            // Add excess zero bits.
118            let candidate = [given_bits, vec![false; i]].concat();
119
120            let candidate = Signature::<CurrentNetwork>::from_bits_be(&candidate)?;
121            assert_eq!(expected, candidate);
122            assert_eq!(Signature::<CurrentNetwork>::size_in_bits(), candidate.to_bits_be().len());
123        }
124        Ok(())
125    }
126
127    #[test]
128    fn test_from_bits_le() -> Result<()> {
129        check_from_bits_le()
130    }
131
132    #[test]
133    fn test_from_bits_be() -> Result<()> {
134        check_from_bits_be()
135    }
136}
snarkvm_console_account/signature/from_bits.rs

snarkvm_console_account/signature/
from_bits.rs
