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