1use crate::group::CompressedGroup;
 2use super::scalar::Scalar;
 3use merlin::Transcript;
 4use ark_ff::{PrimeField, BigInteger};
 5use ark_serialize::{CanonicalSerialize};
 6
 7pub trait ProofTranscript {
 8  fn append_protocol_name(&mut self, protocol_name: &'static [u8]);
 9  fn append_scalar(&mut self, label: &'static [u8], scalar: &Scalar);
10  fn append_point(&mut self, label: &'static [u8], point: &CompressedGroup);
11  fn challenge_scalar(&mut self, label: &'static [u8]) -> Scalar;
12  fn challenge_vector(&mut self, label: &'static [u8], len: usize) -> Vec<Scalar>;
13}
14
15impl ProofTranscript for Transcript {
16  fn append_protocol_name(&mut self, protocol_name: &'static [u8]) {
17    self.append_message(b"protocol-name", protocol_name);
18  }
19
20  fn append_scalar(&mut self, label: &'static [u8], scalar: &Scalar) {
21    self.append_message(label, &scalar.into_repr().to_bytes_le().as_slice());
22  }
23
24  fn append_point(&mut self, label: &'static [u8], point: &CompressedGroup) {
25    let mut point_encoded = Vec::new();
26    point.serialize(&mut point_encoded).unwrap();
27    self.append_message(label, point_encoded.as_slice());
28  }
29
30  fn challenge_scalar(&mut self, label: &'static [u8]) -> Scalar {
31    let mut buf = [0u8; 64];
32    self.challenge_bytes(label, &mut buf);
33    Scalar::from_le_bytes_mod_order(&buf)
34  }
35
36  fn challenge_vector(&mut self, label: &'static [u8], len: usize) -> Vec<Scalar> {
37    (0..len)
38      .map(|_i| self.challenge_scalar(label))
39      .collect::<Vec<Scalar>>()
40  }
41}
42
43pub trait AppendToTranscript {
44  fn append_to_transcript(&self, label: &'static [u8], transcript: &mut Transcript);
45}
46
47impl AppendToTranscript for Scalar {
48  fn append_to_transcript(&self, label: &'static [u8], transcript: &mut Transcript) {
49    transcript.append_scalar(label, self);
50  }
51}
52
53impl AppendToTranscript for [Scalar] {
54  fn append_to_transcript(&self, label: &'static [u8], transcript: &mut Transcript) {
55    transcript.append_message(label, b"begin_append_vector");
56    for item in self {
57      transcript.append_scalar(label, item);
58    }
59    transcript.append_message(label, b"end_append_vector");
60  }
61}
62
63impl AppendToTranscript for CompressedGroup {
64  fn append_to_transcript(&self, label: &'static [u8], transcript: &mut Transcript) {
65    transcript.append_point(label, self);
66  }
67}