Relax Arc requirement for parameters (tari-project#102)

This PR relaxes the `Arc` requirement for parameters.

Specifically, it removes the requirement that the caller use an `Arc` wrapper for `TriptychParameters`. Instead, this wrapping is handled internally.

Closes tari-project#65.

BREAKING CHANGE: Updates the public API.

benches/parallel.rs

@@ -5,9 +5,6 @@
 
 #[macro_use]
 extern crate criterion;
-extern crate alloc;
-
-use alloc::sync::Arc;
 
 use criterion::{BatchSize, Criterion};
 use curve25519_dalek::{RistrettoPoint, Scalar};
@@ -33,7 +30,7 @@ const BATCH_SIZES: [usize; 1] = [2];
 #[allow(non_snake_case)]
 #[allow(clippy::arithmetic_side_effects)]
 fn generate_data<R: CryptoRngCore>(
- params: &Arc<TriptychParameters>,
+ params: &TriptychParameters,
  b: usize,
  rng: &mut R,
 ) -> (Vec<TriptychWitness>, Vec<TriptychStatement>, Vec<Transcript>) {
@@ -94,7 +91,7 @@ fn generate_proof(c: &mut Criterion) {
  for n in N_VALUES {
  for m in M_VALUES {
  // Generate parameters
- let params = Arc::new(TriptychParameters::new(n, m).unwrap());
+ let params = TriptychParameters::new(n, m).unwrap();
 
  let label = format!("Generate proof: n = {}, m = {} (N = {})", n, m, params.get_N());
  group.bench_function(&label, |b| {
@@ -125,7 +122,7 @@ fn generate_proof_vartime(c: &mut Criterion) {
  for n in N_VALUES {
  for m in M_VALUES {
  // Generate parameters
- let params = Arc::new(TriptychParameters::new(n, m).unwrap());
+ let params = TriptychParameters::new(n, m).unwrap();
 
  let label = format!(
  "Generate proof (variable time): n = {}, m = {} (N = {})",
@@ -161,7 +158,7 @@ fn verify_proof(c: &mut Criterion) {
  for n in N_VALUES {
  for m in M_VALUES {
  // Generate parameters
- let params = Arc::new(TriptychParameters::new(n, m).unwrap());
+ let params = TriptychParameters::new(n, m).unwrap();
 
  let label = format!("Verify proof: n = {}, m = {} (N = {})", n, m, params.get_N());
  group.bench_function(&label, |b| {
@@ -197,7 +194,7 @@ fn verify_batch_proof(c: &mut Criterion) {
  for n in N_VALUES {
  for m in M_VALUES {
  // Generate parameters
- let params = Arc::new(TriptychParameters::new(n, m).unwrap());
+ let params = TriptychParameters::new(n, m).unwrap();
 
  for batch in BATCH_SIZES {
  let label = format!(

benches/triptych.rs

@@ -5,9 +5,6 @@
 
 #[macro_use]
 extern crate criterion;
-extern crate alloc;
-
-use alloc::sync::Arc;
 
 use criterion::{BatchSize, Criterion};
 use curve25519_dalek::{RistrettoPoint, Scalar};
@@ -31,7 +28,7 @@ const BATCH_SIZES: [usize; 1] = [2];
 #[allow(non_snake_case)]
 #[allow(clippy::arithmetic_side_effects)]
 fn generate_data<R: CryptoRngCore>(
- params: &Arc<TriptychParameters>,
+ params: &TriptychParameters,
  b: usize,
  rng: &mut R,
 ) -> (Vec<TriptychWitness>, Vec<TriptychStatement>, Vec<Transcript>) {
@@ -84,7 +81,7 @@ fn generate_proof(c: &mut Criterion) {
  for n in N_VALUES {
  for m in M_VALUES {
  // Generate parameters
- let params = Arc::new(TriptychParameters::new(n, m).unwrap());
+ let params = TriptychParameters::new(n, m).unwrap();
 
  let label = format!("Generate proof: n = {}, m = {} (N = {})", n, m, params.get_N());
  group.bench_function(&label, |b| {
@@ -115,7 +112,7 @@ fn generate_proof_vartime(c: &mut Criterion) {
  for n in N_VALUES {
  for m in M_VALUES {
  // Generate parameters
- let params = Arc::new(TriptychParameters::new(n, m).unwrap());
+ let params = TriptychParameters::new(n, m).unwrap();
 
  let label = format!(
  "Generate proof (variable time): n = {}, m = {} (N = {})",
@@ -151,7 +148,7 @@ fn verify_proof(c: &mut Criterion) {
  for n in N_VALUES {
  for m in M_VALUES {
  // Generate parameters
- let params = Arc::new(TriptychParameters::new(n, m).unwrap());
+ let params = TriptychParameters::new(n, m).unwrap();
 
  let label = format!("Verify proof: n = {}, m = {} (N = {})", n, m, params.get_N());
  group.bench_function(&label, |b| {
@@ -187,7 +184,7 @@ fn verify_batch_proof(c: &mut Criterion) {
  for n in N_VALUES {
  for m in M_VALUES {
  // Generate parameters
- let params = Arc::new(TriptychParameters::new(n, m).unwrap());
+ let params = TriptychParameters::new(n, m).unwrap();
 
  for batch in BATCH_SIZES {
  let label = format!(

examples/ringct.rs

@@ -10,8 +10,6 @@
 //! This example shows how to use Triptych.
 #[cfg(test)]
 mod test {
- use std::sync::Arc;
-
  use curve25519_dalek::{RistrettoPoint, Scalar};
  use merlin::Transcript;
  use rand_chacha::ChaCha12Rng;
@@ -25,10 +23,9 @@ mod test {
  let mut rng = ChaCha12Rng::seed_from_u64(8675309);
 
  // Parameters that will define the number of outputs used in the proof: 2^4 == 16
- // The parameters are `Arc`-wrapped since it's likely they could be reused
  let n = 2;
  let m = 4;
- let params = Arc::new(TriptychParameters::new(n, m).unwrap());
+ let params = TriptychParameters::new(n, m).unwrap();
  let number_outputs = params.get_N();
 
  // Value commitments use the Triptych `G` generator for masks, and need another component for values

src/lib.rs

@@ -67,20 +67,16 @@
 //! ```
 //! # #[cfg(feature = "rand")]
 //! # {
-//! # extern crate alloc;
-//! use alloc::sync::Arc;
-//!
 //! use curve25519_dalek::RistrettoPoint;
 //! use rand_core::OsRng;
 //! use triptych::*;
 //!
 //! let mut rng = OsRng;
 //!
 //! // Generate parameters
-//! // This is `Arc`-wrapped to facilitate efficient reuse!
 //! const n: u32 = 2;
 //! const m: u32 = 3;
-//! let params = Arc::new(TriptychParameters::new(n, m).unwrap());
+//! let params = TriptychParameters::new(n, m).unwrap();
 //!
 //! // Generate a random witness, which includes the signing key and an index where it will appear
 //! let witness = TriptychWitness::random(&params, &mut rng);

src/parallel/mod.rs

@@ -21,20 +21,16 @@
 //! ```
 //! # #[cfg(feature = "rand")]
 //! # {
-//! # extern crate alloc;
-//! use alloc::sync::Arc;
-//!
 //! use curve25519_dalek::{RistrettoPoint, Scalar};
 //! use rand_core::OsRng;
 //! use triptych::{parallel::*, Transcript};
 //!
 //! let mut rng = OsRng;
 //!
 //! // Generate parameters
-//! // This is `Arc`-wrapped to facilitate efficient reuse!
 //! const n: u32 = 2;
 //! const m: u32 = 3;
-//! let params = Arc::new(TriptychParameters::new(n, m).unwrap());
+//! let params = TriptychParameters::new(n, m).unwrap();
 //!
 //! // Generate a random witness, which includes the signing key, auxiliary key, and an index where they will appear
 //! let witness = TriptychWitness::random(&params, &mut rng);

src/parallel/parameters.rs

@@ -1,7 +1,7 @@
 // Copyright (c) 2024, The Tari Project
 // SPDX-License-Identifier: BSD-3-Clause
 
-use alloc::{vec, vec::Vec};
+use alloc::{sync::Arc, vec, vec::Vec};
 use core::iter::once;
 
 use blake3::Hasher;
@@ -29,7 +29,7 @@ pub struct TriptychParameters {
  G: RistrettoPoint,
  G1: RistrettoPoint,
  U: RistrettoPoint,
- CommitmentG: Vec<RistrettoPoint>,
+ CommitmentG: Arc<Vec<RistrettoPoint>>,
  CommitmentH: RistrettoPoint,
  hash: Vec<u8>,
 }
@@ -149,7 +149,7 @@ impl TriptychParameters {
  G: *G,
  G1: *G1,
  U: *U,
- CommitmentG,
+ CommitmentG: Arc::new(CommitmentG),
  CommitmentH,
  hash,
  })

src/parallel/proof.rs

@@ -1022,7 +1022,7 @@ impl BorshDeserialize for TriptychProof {
 
 #[cfg(test)]
 mod test {
- use alloc::{sync::Arc, vec::Vec};
+ use alloc::vec::Vec;
 
  use curve25519_dalek::{traits::Identity, RistrettoPoint, Scalar};
  use itertools::izip;
@@ -1061,7 +1061,7 @@ mod test {
  rng: &mut R,
  ) -> (Vec<TriptychWitness>, Vec<TriptychStatement>, Vec<Transcript>) {
  // Generate parameters
- let params = Arc::new(TriptychParameters::new(n, m).unwrap());
+ let params = TriptychParameters::new(n, m).unwrap();
 
  // Generate witnesses; for this test, we use adjacent indexes for simplicity
  // This means the batch size must not exceed the input set size!
@@ -1090,7 +1090,7 @@ mod test {
  offsets.push(r_offset * params.get_G1());
  M1[witness.get_l() as usize] = witness.compute_auxiliary_verification_key() + offsets.last().unwrap();
  }
- let input_set = Arc::new(TriptychInputSet::new(&M, &M1).unwrap());
+ let input_set = TriptychInputSet::new(&M, &M1).unwrap();
 
  // Generate statements
  let mut statements = Vec::with_capacity(b);
@@ -1375,7 +1375,7 @@ mod test {
  let M1 = statements[0].get_input_set().get_auxiliary_keys().to_vec();
  let index = ((witnesses[0].get_l() + 1) % witnesses[0].get_params().get_N()) as usize;
  M[index] = RistrettoPoint::random(&mut rng);
- let evil_input_set = Arc::new(TriptychInputSet::new(&M, &M1).unwrap());
+ let evil_input_set = TriptychInputSet::new(&M, &M1).unwrap();
  let evil_statement = TriptychStatement::new(
  statements[0].get_params(),
  &evil_input_set,
@@ -1407,7 +1407,7 @@ mod test {
  let mut M1 = statements[0].get_input_set().get_auxiliary_keys().to_vec();
  let index = ((witnesses[0].get_l() + 1) % witnesses[0].get_params().get_N()) as usize;
  M1[index] = RistrettoPoint::random(&mut rng);
- let evil_input_set = Arc::new(TriptychInputSet::new(&M, &M1).unwrap());
+ let evil_input_set = TriptychInputSet::new(&M, &M1).unwrap();
  let evil_statement = TriptychStatement::new(
  statements[0].get_params(),
  &evil_input_set,

src/parallel/statement.rs

@@ -129,7 +129,7 @@ impl TriptychInputSet {
 #[allow(non_snake_case)]
 #[derive(Clone, Eq, PartialEq)]
 pub struct TriptychStatement {
- params: Arc<TriptychParameters>,
+ params: TriptychParameters,
  input_set: TriptychInputSet,
  offset: RistrettoPoint,
  J: RistrettoPoint,
@@ -161,7 +161,7 @@ impl TriptychStatement {
  /// otherwise provided externally.
  #[allow(non_snake_case)]
  pub fn new(
- params: &Arc<TriptychParameters>,
+ params: &TriptychParameters,
  input_set: &TriptychInputSet,
  offset: &RistrettoPoint,
  J: &RistrettoPoint,
@@ -203,7 +203,7 @@ impl TriptychStatement {
  }
 
  /// Get the parameters for this [`TriptychStatement`].
- pub fn get_params(&self) -> &Arc<TriptychParameters> {
+ pub fn get_params(&self) -> &TriptychParameters {
  &self.params
  }
 

src/parallel/witness.rs

@@ -1,8 +1,6 @@
 // Copyright (c) 2024, The Tari Project
 // SPDX-License-Identifier: BSD-3-Clause
 
-use alloc::sync::Arc;
-
 use curve25519_dalek::{RistrettoPoint, Scalar};
 use rand_core::CryptoRngCore;
 use snafu::prelude::*;
@@ -18,7 +16,7 @@ use crate::parallel::TriptychParameters;
 #[derive(Zeroize, ZeroizeOnDrop)]
 pub struct TriptychWitness {
  #[zeroize(skip)]
- params: Arc<TriptychParameters>,
+ params: TriptychParameters,
  l: u32,
  r: Scalar,
  r1: Scalar,
@@ -40,7 +38,7 @@ impl TriptychWitness {
  ///
  /// If you'd like a [`TriptychWitness`] generated securely for you, use [`TriptychWitness::random`] instead.
  #[allow(non_snake_case)]
- pub fn new(params: &Arc<TriptychParameters>, l: u32, r: &Scalar, r1: &Scalar) -> Result<Self, WitnessError> {
+ pub fn new(params: &TriptychParameters, l: u32, r: &Scalar, r1: &Scalar) -> Result<Self, WitnessError> {
  if r == &Scalar::ZERO || r1 == &Scalar::ZERO {
  return Err(WitnessError::InvalidParameter);
  }
@@ -63,7 +61,7 @@ impl TriptychWitness {
  ///
  /// If you'd rather provide your own secret data, use [`TriptychWitness::new`] instead.
  #[allow(clippy::cast_possible_truncation)]
- pub fn random<R: CryptoRngCore>(params: &Arc<TriptychParameters>, rng: &mut R) -> Self {
+ pub fn random<R: CryptoRngCore>(params: &TriptychParameters, rng: &mut R) -> Self {
  // Generate a random index using wide reduction
  // This can't truncate since `N` is bounded by `u32`
  // It is also defined since `N > 0`
@@ -79,7 +77,7 @@ impl TriptychWitness {
  }
 
  /// Get the [`TriptychParameters`] from this [`TriptychWitness`].
- pub fn get_params(&self) -> &Arc<TriptychParameters> {
+ pub fn get_params(&self) -> &TriptychParameters {
  &self.params
  }
 

src/parameters.rs

@@ -1,7 +1,7 @@
 // Copyright (c) 2024, The Tari Project
 // SPDX-License-Identifier: BSD-3-Clause
 
-use alloc::{vec, vec::Vec};
+use alloc::{sync::Arc, vec, vec::Vec};
 use core::iter::once;
 
 use blake3::Hasher;
@@ -28,7 +28,7 @@ pub struct TriptychParameters {
  m: u32,
  G: RistrettoPoint,
  U: RistrettoPoint,
- CommitmentG: Vec<RistrettoPoint>,
+ CommitmentG: Arc<Vec<RistrettoPoint>>,
  CommitmentH: RistrettoPoint,
  hash: Vec<u8>,
 }
@@ -132,7 +132,7 @@ impl TriptychParameters {
  m,
  G: *G,
  U: *U,
- CommitmentG,
+ CommitmentG: Arc::new(CommitmentG),
  CommitmentH,
  hash,
  })

src/proof.rs

@@ -941,7 +941,7 @@ impl BorshDeserialize for TriptychProof {
 
 #[cfg(test)]
 mod test {
- use alloc::{sync::Arc, vec::Vec};
+ use alloc::vec::Vec;
 
  use curve25519_dalek::{traits::Identity, RistrettoPoint, Scalar};
  use itertools::izip;
@@ -978,7 +978,7 @@ mod test {
  rng: &mut R,
  ) -> (Vec<TriptychWitness>, Vec<TriptychStatement>, Vec<Transcript>) {
  // Generate parameters
- let params = Arc::new(TriptychParameters::new(n, m).unwrap());
+ let params = TriptychParameters::new(n, m).unwrap();
 
  // Generate witnesses; for this test, we use adjacent indexes for simplicity
  // This means the batch size must not exceed the input set size!

src/statement.rs

@@ -98,7 +98,7 @@ impl TriptychInputSet {
 #[allow(non_snake_case)]
 #[derive(Clone, Eq, PartialEq)]
 pub struct TriptychStatement {
- params: Arc<TriptychParameters>,
+ params: TriptychParameters,
  input_set: TriptychInputSet,
  J: RistrettoPoint,
  hash: Vec<u8>,
@@ -129,7 +129,7 @@ impl TriptychStatement {
  /// otherwise provided externally.
  #[allow(non_snake_case)]
  pub fn new(
- params: &Arc<TriptychParameters>,
+ params: &TriptychParameters,
  input_set: &TriptychInputSet,
  J: &RistrettoPoint,
  ) -> Result<Self, StatementError> {
@@ -159,7 +159,7 @@ impl TriptychStatement {
  }
 
  /// Get the parameters for this [`TriptychStatement`].
- pub fn get_params(&self) -> &Arc<TriptychParameters> {
+ pub fn get_params(&self) -> &TriptychParameters {
  &self.params
  }