feat!: use transcript composition

benches/range_proof.rs

@@ -11,6 +11,7 @@ extern crate criterion;
 
 use criterion::{Criterion, SamplingMode};
 use curve25519_dalek::scalar::Scalar;
+use merlin::Transcript;
 use rand_chacha::ChaCha12Rng;
 use rand_core::{CryptoRngCore, SeedableRng};
 use tari_bulletproofs_plus::{
@@ -92,7 +93,12 @@ fn create_aggregated_rangeproof_helper(bit_length: usize, extension_degree: Exte
  // Benchmark this code
  b.iter(|| {
  // 4. Create the aggregated proof
- let _proof = RistrettoRangeProof::prove_with_rng(transcript_label, &statement, &witness, &mut rng);
+ let _proof = RistrettoRangeProof::prove_with_rng(
+ &mut Transcript::new(transcript_label.as_bytes()),
+ &statement,
+ &witness,
+ &mut rng,
+ );
  })
  });
  }
@@ -131,7 +137,7 @@ fn verify_aggregated_rangeproof_helper(bit_length: usize, extension_degree: Exte
  // 0. Batch data
  let mut statements = vec![];
  let mut proofs = vec![];
- let mut transcript_labels = vec![];
+ let mut transcripts = vec![];
 
  // 1. Generators
  let generators = RangeParameters::init(bit_length, aggregation_factor, pederson_gens.clone()).unwrap();
@@ -163,17 +169,18 @@ fn verify_aggregated_rangeproof_helper(bit_length: usize, extension_degree: Exte
  let statement =
  RangeStatement::init(generators, commitments.clone(), minimum_values.clone(), seed_nonce).unwrap();
  statements.push(statement.clone());
- transcript_labels.push(transcript_label);
+ let mut transcript = Transcript::new(transcript_label.as_bytes());
+ transcripts.push(transcript.clone());
 
  // 4. Create the proof
- let proof = RistrettoRangeProof::prove_with_rng(transcript_label, &statement, &witness, &mut rng).unwrap();
+ let proof = RistrettoRangeProof::prove_with_rng(&mut transcript, &statement, &witness, &mut rng).unwrap();
  proofs.push(proof);
 
  // Benchmark this code
  b.iter(|| {
  // 5. Verify the aggregated proof
  let _masks =
- RangeProof::verify_batch(&transcript_labels, &statements, &proofs, VerifyAction::VerifyOnly)
+ RangeProof::verify_batch(&mut transcripts.clone(), &statements, &proofs, VerifyAction::VerifyOnly)
  .unwrap();
  });
  });
@@ -218,7 +225,7 @@ fn verify_batched_rangeproofs_helper(bit_length: usize, extension_degree: Extens
  // Batch data
  let mut statements = vec![];
  let mut proofs = vec![];
- let mut transcript_labels = vec![];
+ let mut transcripts = vec![];
 
  for _ in 0..number_of_range_proofs {
  // Witness data
@@ -241,11 +248,12 @@ fn verify_batched_rangeproofs_helper(bit_length: usize, extension_degree: Extens
  )
  .unwrap();
  statements.push(statement.clone());
- transcript_labels.push(transcript_label);
+ let mut transcript = Transcript::new(transcript_label.as_bytes());
+ transcripts.push(transcript.clone());
 
  // Proof
  let proof =
- RistrettoRangeProof::prove_with_rng(transcript_label, &statement, &witness, &mut rng).unwrap();
+ RistrettoRangeProof::prove_with_rng(&mut transcript, &statement, &witness, &mut rng).unwrap();
  proofs.push(proof);
  }
 
@@ -255,7 +263,7 @@ fn verify_batched_rangeproofs_helper(bit_length: usize, extension_degree: Extens
  match extract_masks {
  VerifyAction::VerifyOnly => {
  let _masks = RangeProof::verify_batch(
- &transcript_labels,
+ &mut transcripts.clone(),
  &statements,
  &proofs,
  VerifyAction::VerifyOnly,
@@ -264,7 +272,7 @@ fn verify_batched_rangeproofs_helper(bit_length: usize, extension_degree: Extens
  },
  VerifyAction::RecoverOnly => {
  let _masks = RangeProof::verify_batch(
- &transcript_labels,
+ &mut transcripts.clone(),
  &statements,
  &proofs,
  VerifyAction::RecoverOnly,

src/lib.rs

@@ -34,5 +34,7 @@ mod utils;
 pub use generators::bulletproof_gens::BulletproofGens;
 /// Bulletproofs+ generators and base points needed for a batch of range proofs
 pub use generators::pedersen_gens::PedersenGens;
+/// Merlin transcripts
+pub use merlin::Transcript;
 
 pub mod ristretto;

src/protocols/transcript_protocol.rs

@@ -15,8 +15,8 @@ use crate::{errors::ProofError, traits::FixedBytesRepr};
 
 /// Defines a `TranscriptProtocol` trait for using a Merlin transcript.
 pub trait TranscriptProtocol {
- /// Append a domain separator for the range proof with the given `label` and `message`.
- fn domain_separator(&mut self, label: &'static [u8], message: &[u8]);
+ /// Append a domain separator for the range proof.
+ fn append_domain_separator(&mut self);
 
  /// Append a `point` with the given `label`.
  fn append_point<P: FixedBytesRepr>(&mut self, label: &'static [u8], point: &P);
@@ -37,8 +37,8 @@ pub trait TranscriptProtocol {
 }
 
 impl TranscriptProtocol for Transcript {
- fn domain_separator(&mut self, label: &'static [u8], message: &[u8]) {
- self.append_message(label, message);
+ fn append_domain_separator(&mut self) {
+ self.append_message(b"dom-sep", b"Bulletproofs+ Range Proof");
  }
 
  fn append_point<P: FixedBytesRepr>(&mut self, label: &'static [u8], point: &P) {