Smash out monero-bulletproofs

Removes usage of dalek-ff-group/multiexp for curve25519-dalek.

Makes compiling in the generators an optional feature.

Adds a structured batch verifier which should be notably more performant.

Documentation and clean up still necessary.
This commit is contained in:
Luke Parker
2024-06-15 17:00:11 -04:00
parent 798ffc9b28
commit f7c13fd1ca
32 changed files with 716 additions and 502 deletions

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[package]
name = "monero-bulletproofs"
version = "0.1.0"
description = "Bulletproofs(+) range proofs, as defined by the Monero protocol"
license = "MIT"
repository = "https://github.com/serai-dex/serai/tree/develop/coins/monero/ringct/bulletproofs"
authors = ["Luke Parker <lukeparker5132@gmail.com>"]
edition = "2021"
rust-version = "1.79"
[package.metadata.docs.rs]
all-features = true
rustdoc-args = ["--cfg", "docsrs"]
[lints]
workspace = true
[dependencies]
std-shims = { path = "../../../../common/std-shims", version = "^0.1.1", default-features = false }
thiserror = { version = "1", default-features = false, optional = true }
rand_core = { version = "0.6", default-features = false }
zeroize = { version = "^1.5", default-features = false, features = ["zeroize_derive"] }
subtle = { version = "^2.4", default-features = false }
# Cryptographic dependencies
curve25519-dalek = { version = "4", default-features = false, features = ["alloc", "zeroize"] }
# Other Monero dependencies
monero-io = { path = "../../io", version = "0.1", default-features = false }
monero-generators = { path = "../../generators", version = "0.4", default-features = false }
monero-primitives = { path = "../../primitives", version = "0.1", default-features = false }
[build-dependencies]
curve25519-dalek = { version = "4", default-features = false, features = ["alloc", "zeroize"] }
monero-generators = { path = "../../generators", version = "0.4", default-features = false }
[dev-dependencies]
hex-literal = "0.4"
[features]
std = [
"std-shims/std",
"thiserror",
"rand_core/std",
"zeroize/std",
"subtle/std",
"monero-io/std",
"monero-generators/std",
"monero-primitives/std",
]
compile-time-generators = ["curve25519-dalek/precomputed-tables"]
default = ["std"]

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MIT License
Copyright (c) 2022-2024 Luke Parker
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

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# Monero Bulletproofs(+)
Bulletproofs(+) range proofs, as defined by the Monero protocol.
This library is usable under no-std when the `std` feature (on by default) is
disabled.

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use std::{
io::Write,
env,
path::Path,
fs::{File, remove_file},
};
#[cfg(feature = "compile-time-generators")]
fn generators(prefix: &'static str, path: &str) {
use curve25519_dalek::EdwardsPoint;
use monero_generators::bulletproofs_generators;
fn serialize(generators_string: &mut String, points: &[EdwardsPoint]) {
for generator in points {
generators_string.extend(
format!(
"
curve25519_dalek::edwards::CompressedEdwardsY({:?}).decompress().unwrap(),
",
generator.compress().to_bytes()
)
.chars(),
);
}
}
let generators = bulletproofs_generators(prefix.as_bytes());
#[allow(non_snake_case)]
let mut G_str = String::new();
serialize(&mut G_str, &generators.G);
#[allow(non_snake_case)]
let mut H_str = String::new();
serialize(&mut H_str, &generators.H);
let path = Path::new(&env::var("OUT_DIR").unwrap()).join(path);
let _ = remove_file(&path);
File::create(&path)
.unwrap()
.write_all(
format!(
"
static GENERATORS_CELL: OnceLock<Generators> = OnceLock::new();
pub(crate) fn GENERATORS() -> &'static Generators {{
GENERATORS_CELL.get_or_init(|| Generators {{
G: vec![
{G_str}
],
H: vec![
{H_str}
],
}})
}}
",
)
.as_bytes(),
)
.unwrap();
}
#[cfg(not(feature = "compile-time-generators"))]
fn generators(prefix: &'static str, path: &str) {
let path = Path::new(&env::var("OUT_DIR").unwrap()).join(path);
let _ = remove_file(&path);
File::create(&path)
.unwrap()
.write_all(
format!(
r#"
static GENERATORS_CELL: OnceLock<Generators> = OnceLock::new();
pub(crate) fn GENERATORS() -> &'static Generators {{
GENERATORS_CELL.get_or_init(|| {{
monero_generators::bulletproofs_generators(b"{prefix}")
}})
}}
"#,
)
.as_bytes(),
)
.unwrap();
}
fn main() {
println!("cargo:rerun-if-changed=build.rs");
generators("bulletproof", "generators.rs");
generators("bulletproof_plus", "generators_plus.rs");
}

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use curve25519_dalek::{
constants::ED25519_BASEPOINT_POINT,
traits::{IsIdentity, VartimeMultiscalarMul},
scalar::Scalar,
edwards::EdwardsPoint,
};
use monero_generators::{H, Generators};
use crate::{original, plus};
#[derive(Default)]
pub(crate) struct InternalBatchVerifier {
pub(crate) g: Scalar,
pub(crate) h: Scalar,
pub(crate) g_bold: Vec<Scalar>,
pub(crate) h_bold: Vec<Scalar>,
pub(crate) other: Vec<(Scalar, EdwardsPoint)>,
}
impl InternalBatchVerifier {
pub fn new() -> Self {
Self { g: Scalar::ZERO, h: Scalar::ZERO, g_bold: vec![], h_bold: vec![], other: vec![] }
}
#[must_use]
pub fn verify(self, G: EdwardsPoint, H: EdwardsPoint, generators: &Generators) -> bool {
let capacity = 2 + self.g_bold.len() + self.h_bold.len() + self.other.len();
let mut scalars = Vec::with_capacity(capacity);
let mut points = Vec::with_capacity(capacity);
scalars.push(self.g);
points.push(G);
scalars.push(self.h);
points.push(H);
for (i, g_bold) in self.g_bold.into_iter().enumerate() {
scalars.push(g_bold);
points.push(generators.G[i]);
}
for (i, h_bold) in self.h_bold.into_iter().enumerate() {
scalars.push(h_bold);
points.push(generators.H[i]);
}
for (scalar, point) in self.other {
scalars.push(scalar);
points.push(point);
}
EdwardsPoint::vartime_multiscalar_mul(scalars, points).is_identity()
}
}
#[derive(Default)]
pub(crate) struct BulletproofsBatchVerifier(pub(crate) InternalBatchVerifier);
impl BulletproofsBatchVerifier {
#[must_use]
pub fn verify(self) -> bool {
self.0.verify(ED25519_BASEPOINT_POINT, H(), original::GENERATORS())
}
}
#[derive(Default)]
pub(crate) struct BulletproofsPlusBatchVerifier(pub(crate) InternalBatchVerifier);
impl BulletproofsPlusBatchVerifier {
#[must_use]
pub fn verify(self) -> bool {
// Bulletproofs+ is written as per the paper, with G for the value and H for the mask
// Monero uses H for the value and G for the mask
self.0.verify(H(), ED25519_BASEPOINT_POINT, plus::GENERATORS())
}
}
#[derive(Default)]
pub struct BatchVerifier {
pub(crate) original: BulletproofsBatchVerifier,
pub(crate) plus: BulletproofsPlusBatchVerifier,
}
impl BatchVerifier {
pub fn new() -> Self {
Self {
original: BulletproofsBatchVerifier(InternalBatchVerifier::new()),
plus: BulletproofsPlusBatchVerifier(InternalBatchVerifier::new()),
}
}
#[must_use]
pub fn verify(self) -> bool {
self.original.verify() && self.plus.verify()
}
}

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use std_shims::{vec::Vec, sync::OnceLock};
use rand_core::{RngCore, CryptoRng};
use subtle::{Choice, ConditionallySelectable};
use curve25519_dalek::{
constants::ED25519_BASEPOINT_TABLE,
traits::{MultiscalarMul, VartimeMultiscalarMul},
scalar::Scalar,
edwards::EdwardsPoint,
};
pub(crate) use monero_generators::Generators;
use monero_primitives::{INV_EIGHT, Commitment, keccak256_to_scalar};
pub(crate) use crate::scalar_vector::*;
// Components common between variants
// TODO: Move to generators? primitives?
pub(crate) const MAX_M: usize = 16;
pub(crate) const LOG_N: usize = 6; // 2 << 6 == N
pub(crate) const N: usize = 64;
pub(crate) fn multiexp(pairs: &[(Scalar, EdwardsPoint)]) -> EdwardsPoint {
let mut buf_scalars = Vec::with_capacity(pairs.len());
let mut buf_points = Vec::with_capacity(pairs.len());
for (scalar, point) in pairs {
buf_scalars.push(scalar);
buf_points.push(point);
}
EdwardsPoint::multiscalar_mul(buf_scalars, buf_points)
}
pub(crate) fn multiexp_vartime(pairs: &[(Scalar, EdwardsPoint)]) -> EdwardsPoint {
let mut buf_scalars = Vec::with_capacity(pairs.len());
let mut buf_points = Vec::with_capacity(pairs.len());
for (scalar, point) in pairs {
buf_scalars.push(scalar);
buf_points.push(point);
}
EdwardsPoint::vartime_multiscalar_mul(buf_scalars, buf_points)
}
pub(crate) fn vector_exponent(
generators: &Generators,
a: &ScalarVector,
b: &ScalarVector,
) -> EdwardsPoint {
debug_assert_eq!(a.len(), b.len());
(a * &generators.G[.. a.len()]) + (b * &generators.H[.. b.len()])
}
pub(crate) fn hash_cache(cache: &mut Scalar, mash: &[[u8; 32]]) -> Scalar {
let slice =
&[cache.to_bytes().as_ref(), mash.iter().copied().flatten().collect::<Vec<_>>().as_ref()]
.concat();
*cache = keccak256_to_scalar(slice);
*cache
}
pub(crate) fn MN(outputs: usize) -> (usize, usize, usize) {
let mut logM = 0;
let mut M;
while {
M = 1 << logM;
(M <= MAX_M) && (M < outputs)
} {
logM += 1;
}
(logM + LOG_N, M, M * N)
}
pub(crate) fn bit_decompose(commitments: &[Commitment]) -> (ScalarVector, ScalarVector) {
let (_, M, MN) = MN(commitments.len());
let sv = commitments.iter().map(|c| Scalar::from(c.amount)).collect::<Vec<_>>();
let mut aL = ScalarVector::new(MN);
let mut aR = ScalarVector::new(MN);
for j in 0 .. M {
for i in (0 .. N).rev() {
let bit =
if j < sv.len() { Choice::from((sv[j][i / 8] >> (i % 8)) & 1) } else { Choice::from(0) };
aL.0[(j * N) + i] = Scalar::conditional_select(&Scalar::ZERO, &Scalar::ONE, bit);
aR.0[(j * N) + i] = Scalar::conditional_select(&-Scalar::ONE, &Scalar::ZERO, bit);
}
}
(aL, aR)
}
pub(crate) fn hash_commitments<C: IntoIterator<Item = EdwardsPoint>>(
commitments: C,
) -> (Scalar, Vec<EdwardsPoint>) {
let V = commitments.into_iter().map(|c| c * INV_EIGHT()).collect::<Vec<_>>();
(keccak256_to_scalar(V.iter().flat_map(|V| V.compress().to_bytes()).collect::<Vec<_>>()), V)
}
pub(crate) fn alpha_rho<R: RngCore + CryptoRng>(
rng: &mut R,
generators: &Generators,
aL: &ScalarVector,
aR: &ScalarVector,
) -> (Scalar, EdwardsPoint) {
let ar = Scalar::random(rng);
(ar, (vector_exponent(generators, aL, aR) + (ED25519_BASEPOINT_TABLE * &ar)) * INV_EIGHT())
}
pub(crate) fn LR_statements(
a: &ScalarVector,
G_i: &[EdwardsPoint],
b: &ScalarVector,
H_i: &[EdwardsPoint],
cL: Scalar,
U: EdwardsPoint,
) -> Vec<(Scalar, EdwardsPoint)> {
let mut res = a
.0
.iter()
.copied()
.zip(G_i.iter().copied())
.chain(b.0.iter().copied().zip(H_i.iter().copied()))
.collect::<Vec<_>>();
res.push((cL, U));
res
}
static TWO_N_CELL: OnceLock<ScalarVector> = OnceLock::new();
pub(crate) fn TWO_N() -> &'static ScalarVector {
TWO_N_CELL.get_or_init(|| ScalarVector::powers(Scalar::from(2u8), N))
}
pub(crate) fn challenge_products(w: &[Scalar], winv: &[Scalar]) -> Vec<Scalar> {
let mut products = vec![Scalar::ZERO; 1 << w.len()];
products[0] = winv[0];
products[1] = w[0];
for j in 1 .. w.len() {
let mut slots = (1 << (j + 1)) - 1;
while slots > 0 {
products[slots] = products[slots / 2] * w[j];
products[slots - 1] = products[slots / 2] * winv[j];
slots = slots.saturating_sub(2);
}
}
// Sanity check as if the above failed to populate, it'd be critical
for w in &products {
debug_assert!(*w != Scalar::ZERO);
}
products
}

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#![cfg_attr(docsrs, feature(doc_auto_cfg))]
#![doc = include_str!("../README.md")]
#![cfg_attr(not(feature = "std"), no_std)]
#![allow(non_snake_case)]
use std_shims::{
vec::Vec,
io::{self, Read, Write},
};
use rand_core::{RngCore, CryptoRng};
use zeroize::Zeroizing;
use curve25519_dalek::edwards::EdwardsPoint;
use monero_io::*;
use monero_primitives::Commitment;
pub(crate) mod scalar_vector;
pub(crate) mod core;
use crate::core::LOG_N;
pub mod batch_verifier;
use batch_verifier::{InternalBatchVerifier, BulletproofsPlusBatchVerifier, BatchVerifier};
pub(crate) mod original;
use crate::original::OriginalStruct;
pub(crate) mod plus;
use crate::plus::*;
#[cfg(test)]
mod tests;
pub const MAX_COMMITMENTS: usize = crate::core::MAX_M;
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
#[cfg_attr(feature = "std", derive(thiserror::Error))]
pub enum BulletproofError {
#[cfg_attr(feature = "std", error("no commitments to prove the range for"))]
NoCommitments,
#[cfg_attr(feature = "std", error("too many commitments to prove the range for"))]
TooManyCommitments,
}
/// Bulletproof enum, encapsulating both Bulletproofs and Bulletproofs+.
#[allow(clippy::large_enum_variant)]
#[derive(Clone, PartialEq, Eq, Debug)]
pub enum Bulletproof {
Original(OriginalStruct),
Plus(AggregateRangeProof),
}
impl Bulletproof {
fn bp_fields(plus: bool) -> usize {
if plus {
6
} else {
9
}
}
// https://github.com/monero-project/monero/blob/94e67bf96bbc010241f29ada6abc89f49a81759c/
// src/cryptonote_basic/cryptonote_format_utils.cpp#L106-L124
pub fn calculate_bp_clawback(plus: bool, n_outputs: usize) -> (usize, usize) {
#[allow(non_snake_case)]
let mut LR_len = 0;
let mut n_padded_outputs = 1;
while n_padded_outputs < n_outputs {
LR_len += 1;
n_padded_outputs = 1 << LR_len;
}
LR_len += LOG_N;
let mut bp_clawback = 0;
if n_padded_outputs > 2 {
let fields = Bulletproof::bp_fields(plus);
let base = ((fields + (2 * (LOG_N + 1))) * 32) / 2;
let size = (fields + (2 * LR_len)) * 32;
bp_clawback = ((base * n_padded_outputs) - size) * 4 / 5;
}
(bp_clawback, LR_len)
}
pub fn fee_weight(plus: bool, outputs: usize) -> usize {
#[allow(non_snake_case)]
let (bp_clawback, LR_len) = Bulletproof::calculate_bp_clawback(plus, outputs);
32 * (Bulletproof::bp_fields(plus) + (2 * LR_len)) + 2 + bp_clawback
}
/// Prove the list of commitments are within [0 .. 2^64) with an aggregate Bulletproof.
pub fn prove<R: RngCore + CryptoRng>(
rng: &mut R,
outputs: &[Commitment],
) -> Result<Bulletproof, BulletproofError> {
if outputs.is_empty() {
Err(BulletproofError::NoCommitments)?;
}
if outputs.len() > MAX_COMMITMENTS {
Err(BulletproofError::TooManyCommitments)?;
}
Ok(Bulletproof::Original(OriginalStruct::prove(rng, outputs)))
}
/// Prove the list of commitments are within [0 .. 2^64) with an aggregate Bulletproof+.
pub fn prove_plus<R: RngCore + CryptoRng>(
rng: &mut R,
outputs: Vec<Commitment>,
) -> Result<Bulletproof, BulletproofError> {
if outputs.is_empty() {
Err(BulletproofError::NoCommitments)?;
}
if outputs.len() > MAX_COMMITMENTS {
Err(BulletproofError::TooManyCommitments)?;
}
Ok(Bulletproof::Plus(
AggregateRangeStatement::new(outputs.iter().map(Commitment::calculate).collect())
.unwrap()
.prove(rng, &Zeroizing::new(AggregateRangeWitness::new(outputs).unwrap()))
.unwrap(),
))
}
/// Verify the given Bulletproof(+).
#[must_use]
pub fn verify<R: RngCore + CryptoRng>(&self, rng: &mut R, commitments: &[EdwardsPoint]) -> bool {
match self {
Bulletproof::Original(bp) => bp.verify(rng, commitments),
Bulletproof::Plus(bp) => {
let mut verifier = BulletproofsPlusBatchVerifier(InternalBatchVerifier::new());
let Some(statement) = AggregateRangeStatement::new(commitments.to_vec()) else {
return false;
};
if !statement.verify(rng, &mut verifier, bp.clone()) {
return false;
}
verifier.verify()
}
}
}
/// Accumulate the verification for the given Bulletproof into the specified BatchVerifier.
///
/// Returns false if the Bulletproof isn't sane, leaving the BatchVerifier in an undefined
/// state.
/// Returns true if the Bulletproof is sane, regardless of their validity.
#[must_use]
pub fn batch_verify<R: RngCore + CryptoRng>(
&self,
rng: &mut R,
verifier: &mut BatchVerifier,
commitments: &[EdwardsPoint],
) -> bool {
match self {
Bulletproof::Original(bp) => bp.batch_verify(rng, &mut verifier.original, commitments),
Bulletproof::Plus(bp) => {
let Some(statement) = AggregateRangeStatement::new(commitments.to_vec()) else {
return false;
};
statement.verify(rng, &mut verifier.plus, bp.clone())
}
}
}
fn write_core<W: Write, F: Fn(&[EdwardsPoint], &mut W) -> io::Result<()>>(
&self,
w: &mut W,
specific_write_vec: F,
) -> io::Result<()> {
match self {
Bulletproof::Original(bp) => {
write_point(&bp.A, w)?;
write_point(&bp.S, w)?;
write_point(&bp.T1, w)?;
write_point(&bp.T2, w)?;
write_scalar(&bp.tau_x, w)?;
write_scalar(&bp.mu, w)?;
specific_write_vec(&bp.L, w)?;
specific_write_vec(&bp.R, w)?;
write_scalar(&bp.a, w)?;
write_scalar(&bp.b, w)?;
write_scalar(&bp.t, w)
}
Bulletproof::Plus(bp) => {
write_point(&bp.A, w)?;
write_point(&bp.wip.A, w)?;
write_point(&bp.wip.B, w)?;
write_scalar(&bp.wip.r_answer, w)?;
write_scalar(&bp.wip.s_answer, w)?;
write_scalar(&bp.wip.delta_answer, w)?;
specific_write_vec(&bp.wip.L, w)?;
specific_write_vec(&bp.wip.R, w)
}
}
}
pub fn signature_write<W: Write>(&self, w: &mut W) -> io::Result<()> {
self.write_core(w, |points, w| write_raw_vec(write_point, points, w))
}
/// Write the Bulletproof(+) to a writer.
pub fn write<W: Write>(&self, w: &mut W) -> io::Result<()> {
self.write_core(w, |points, w| write_vec(write_point, points, w))
}
/// Serialize the Bulletproof(+) to a `Vec<u8>`.
pub fn serialize(&self) -> Vec<u8> {
let mut serialized = vec![];
self.write(&mut serialized).unwrap();
serialized
}
/// Read a Bulletproof.
pub fn read<R: Read>(r: &mut R) -> io::Result<Bulletproof> {
Ok(Bulletproof::Original(OriginalStruct {
A: read_point(r)?,
S: read_point(r)?,
T1: read_point(r)?,
T2: read_point(r)?,
tau_x: read_scalar(r)?,
mu: read_scalar(r)?,
L: read_vec(read_point, r)?,
R: read_vec(read_point, r)?,
a: read_scalar(r)?,
b: read_scalar(r)?,
t: read_scalar(r)?,
}))
}
/// Read a Bulletproof+.
pub fn read_plus<R: Read>(r: &mut R) -> io::Result<Bulletproof> {
Ok(Bulletproof::Plus(AggregateRangeProof {
A: read_point(r)?,
wip: WipProof {
A: read_point(r)?,
B: read_point(r)?,
r_answer: read_scalar(r)?,
s_answer: read_scalar(r)?,
delta_answer: read_scalar(r)?,
L: read_vec(read_point, r)?.into_iter().collect(),
R: read_vec(read_point, r)?.into_iter().collect(),
},
}))
}
}

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use std_shims::{vec::Vec, sync::OnceLock};
use rand_core::{RngCore, CryptoRng};
use zeroize::Zeroize;
use curve25519_dalek::{constants::ED25519_BASEPOINT_POINT, scalar::Scalar, edwards::EdwardsPoint};
use monero_generators::H;
use monero_primitives::{INV_EIGHT, Commitment, keccak256_to_scalar};
use crate::{
core::*,
batch_verifier::{InternalBatchVerifier, BulletproofsBatchVerifier},
};
include!(concat!(env!("OUT_DIR"), "/generators.rs"));
static IP12_CELL: OnceLock<Scalar> = OnceLock::new();
pub(crate) fn IP12() -> Scalar {
*IP12_CELL.get_or_init(|| ScalarVector(vec![Scalar::ONE; N]).inner_product(TWO_N()))
}
pub(crate) fn hadamard_fold(
l: &[EdwardsPoint],
r: &[EdwardsPoint],
a: Scalar,
b: Scalar,
) -> Vec<EdwardsPoint> {
let mut res = Vec::with_capacity(l.len() / 2);
for i in 0 .. l.len() {
res.push(multiexp(&[(a, l[i]), (b, r[i])]));
}
res
}
/// Internal structure representing a Bulletproof.
#[derive(Clone, PartialEq, Eq, Debug)]
pub struct OriginalStruct {
pub(crate) A: EdwardsPoint,
pub(crate) S: EdwardsPoint,
pub(crate) T1: EdwardsPoint,
pub(crate) T2: EdwardsPoint,
pub(crate) tau_x: Scalar,
pub(crate) mu: Scalar,
pub(crate) L: Vec<EdwardsPoint>,
pub(crate) R: Vec<EdwardsPoint>,
pub(crate) a: Scalar,
pub(crate) b: Scalar,
pub(crate) t: Scalar,
}
impl OriginalStruct {
pub(crate) fn prove<R: RngCore + CryptoRng>(
rng: &mut R,
commitments: &[Commitment],
) -> OriginalStruct {
let (logMN, M, MN) = MN(commitments.len());
let (aL, aR) = bit_decompose(commitments);
let commitments_points = commitments.iter().map(Commitment::calculate).collect::<Vec<_>>();
let (mut cache, _) = hash_commitments(commitments_points.clone());
let (sL, sR) =
ScalarVector((0 .. (MN * 2)).map(|_| Scalar::random(&mut *rng)).collect::<Vec<_>>()).split();
let generators = GENERATORS();
let (mut alpha, A) = alpha_rho(&mut *rng, generators, &aL, &aR);
let (mut rho, S) = alpha_rho(&mut *rng, generators, &sL, &sR);
let y = hash_cache(&mut cache, &[A.compress().to_bytes(), S.compress().to_bytes()]);
let mut cache = keccak256_to_scalar(y.to_bytes());
let z = cache;
let l0 = aL - z;
let l1 = sL;
let mut zero_twos = Vec::with_capacity(MN);
let zpow = ScalarVector::powers(z, M + 2);
for j in 0 .. M {
for i in 0 .. N {
zero_twos.push(zpow[j + 2] * TWO_N()[i]);
}
}
let yMN = ScalarVector::powers(y, MN);
let r0 = ((aR + z) * &yMN) + &ScalarVector(zero_twos);
let r1 = yMN * &sR;
let (T1, T2, x, mut tau_x) = {
let t1 = l0.clone().inner_product(&r1) + r0.clone().inner_product(&l1);
let t2 = l1.clone().inner_product(&r1);
let mut tau1 = Scalar::random(&mut *rng);
let mut tau2 = Scalar::random(&mut *rng);
let T1 = multiexp(&[(t1, H()), (tau1, ED25519_BASEPOINT_POINT)]) * INV_EIGHT();
let T2 = multiexp(&[(t2, H()), (tau2, ED25519_BASEPOINT_POINT)]) * INV_EIGHT();
let x =
hash_cache(&mut cache, &[z.to_bytes(), T1.compress().to_bytes(), T2.compress().to_bytes()]);
let tau_x = (tau2 * (x * x)) + (tau1 * x);
tau1.zeroize();
tau2.zeroize();
(T1, T2, x, tau_x)
};
let mu = (x * rho) + alpha;
alpha.zeroize();
rho.zeroize();
for (i, gamma) in commitments.iter().map(|c| c.mask).enumerate() {
tau_x += zpow[i + 2] * gamma;
}
let l = l0 + &(l1 * x);
let r = r0 + &(r1 * x);
let t = l.clone().inner_product(&r);
let x_ip =
hash_cache(&mut cache, &[x.to_bytes(), tau_x.to_bytes(), mu.to_bytes(), t.to_bytes()]);
let mut a = l;
let mut b = r;
let yinv = y.invert();
let yinvpow = ScalarVector::powers(yinv, MN);
let mut G_proof = generators.G[.. a.len()].to_vec();
let mut H_proof = generators.H[.. a.len()].to_vec();
H_proof.iter_mut().zip(yinvpow.0.iter()).for_each(|(this_H, yinvpow)| *this_H *= yinvpow);
let U = H() * x_ip;
let mut L = Vec::with_capacity(logMN);
let mut R = Vec::with_capacity(logMN);
while a.len() != 1 {
let (aL, aR) = a.split();
let (bL, bR) = b.split();
let cL = aL.clone().inner_product(&bR);
let cR = aR.clone().inner_product(&bL);
let (G_L, G_R) = G_proof.split_at(aL.len());
let (H_L, H_R) = H_proof.split_at(aL.len());
let L_i = multiexp(&LR_statements(&aL, G_R, &bR, H_L, cL, U)) * INV_EIGHT();
let R_i = multiexp(&LR_statements(&aR, G_L, &bL, H_R, cR, U)) * INV_EIGHT();
L.push(L_i);
R.push(R_i);
let w = hash_cache(&mut cache, &[L_i.compress().to_bytes(), R_i.compress().to_bytes()]);
let winv = w.invert();
a = (aL * w) + &(aR * winv);
b = (bL * winv) + &(bR * w);
if a.len() != 1 {
G_proof = hadamard_fold(G_L, G_R, winv, w);
H_proof = hadamard_fold(H_L, H_R, w, winv);
}
}
let res = OriginalStruct { A, S, T1, T2, tau_x, mu, L, R, a: a[0], b: b[0], t };
debug_assert!(res.verify(rng, &commitments_points));
res
}
#[must_use]
fn verify_core<R: RngCore + CryptoRng>(
&self,
rng: &mut R,
verifier: &mut BulletproofsBatchVerifier,
commitments: &[EdwardsPoint],
) -> bool {
// Verify commitments are valid
if commitments.is_empty() || (commitments.len() > MAX_M) {
return false;
}
// Verify L and R are properly sized
if self.L.len() != self.R.len() {
return false;
}
let (logMN, M, MN) = MN(commitments.len());
if self.L.len() != logMN {
return false;
}
// Rebuild all challenges
let (mut cache, commitments) = hash_commitments(commitments.iter().copied());
let y = hash_cache(&mut cache, &[self.A.compress().to_bytes(), self.S.compress().to_bytes()]);
let z = keccak256_to_scalar(y.to_bytes());
cache = z;
let x = hash_cache(
&mut cache,
&[z.to_bytes(), self.T1.compress().to_bytes(), self.T2.compress().to_bytes()],
);
let x_ip = hash_cache(
&mut cache,
&[x.to_bytes(), self.tau_x.to_bytes(), self.mu.to_bytes(), self.t.to_bytes()],
);
let mut w = Vec::with_capacity(logMN);
let mut winv = Vec::with_capacity(logMN);
for (L, R) in self.L.iter().zip(&self.R) {
w.push(hash_cache(&mut cache, &[L.compress().to_bytes(), R.compress().to_bytes()]));
winv.push(cache.invert());
}
// Convert the proof from * INV_EIGHT to its actual form
let normalize = |point: &EdwardsPoint| point.mul_by_cofactor();
let L = self.L.iter().map(normalize).collect::<Vec<_>>();
let R = self.R.iter().map(normalize).collect::<Vec<_>>();
let T1 = normalize(&self.T1);
let T2 = normalize(&self.T2);
let A = normalize(&self.A);
let S = normalize(&self.S);
let commitments = commitments.iter().map(EdwardsPoint::mul_by_cofactor).collect::<Vec<_>>();
// Verify it
let zpow = ScalarVector::powers(z, M + 3);
// First multiexp
{
let verifier_weight = Scalar::random(rng);
let ip1y = ScalarVector::powers(y, M * N).sum();
let mut k = -(zpow[2] * ip1y);
for j in 1 ..= M {
k -= zpow[j + 2] * IP12();
}
let y1 = self.t - ((z * ip1y) + k);
verifier.0.h -= verifier_weight * y1;
verifier.0.g -= verifier_weight * self.tau_x;
for (j, commitment) in commitments.iter().enumerate() {
verifier.0.other.push((verifier_weight * zpow[j + 2], *commitment));
}
verifier.0.other.push((verifier_weight * x, T1));
verifier.0.other.push((verifier_weight * (x * x), T2));
}
// Second multiexp
{
let verifier_weight = Scalar::random(rng);
let z3 = (self.t - (self.a * self.b)) * x_ip;
verifier.0.h += verifier_weight * z3;
verifier.0.g -= verifier_weight * self.mu;
verifier.0.other.push((verifier_weight, A));
verifier.0.other.push((verifier_weight * x, S));
{
let ypow = ScalarVector::powers(y, MN);
let yinv = y.invert();
let yinvpow = ScalarVector::powers(yinv, MN);
let w_cache = challenge_products(&w, &winv);
while verifier.0.g_bold.len() < MN {
verifier.0.g_bold.push(Scalar::ZERO);
}
while verifier.0.h_bold.len() < MN {
verifier.0.h_bold.push(Scalar::ZERO);
}
for i in 0 .. MN {
let g = (self.a * w_cache[i]) + z;
verifier.0.g_bold[i] -= verifier_weight * g;
let mut h = self.b * yinvpow[i] * w_cache[(!i) & (MN - 1)];
h -= ((zpow[(i / N) + 2] * TWO_N()[i % N]) + (z * ypow[i])) * yinvpow[i];
verifier.0.h_bold[i] -= verifier_weight * h;
}
}
for i in 0 .. logMN {
verifier.0.other.push((verifier_weight * (w[i] * w[i]), L[i]));
verifier.0.other.push((verifier_weight * (winv[i] * winv[i]), R[i]));
}
}
true
}
#[must_use]
pub(crate) fn verify<R: RngCore + CryptoRng>(
&self,
rng: &mut R,
commitments: &[EdwardsPoint],
) -> bool {
let mut verifier = BulletproofsBatchVerifier(InternalBatchVerifier::new());
if self.verify_core(rng, &mut verifier, commitments) {
verifier.verify()
} else {
false
}
}
#[must_use]
pub(crate) fn batch_verify<R: RngCore + CryptoRng>(
&self,
rng: &mut R,
verifier: &mut BulletproofsBatchVerifier,
commitments: &[EdwardsPoint],
) -> bool {
self.verify_core(rng, verifier, commitments)
}
}

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@@ -0,0 +1,260 @@
use std_shims::vec::Vec;
use rand_core::{RngCore, CryptoRng};
use zeroize::{Zeroize, ZeroizeOnDrop, Zeroizing};
use curve25519_dalek::{traits::Identity, scalar::Scalar, edwards::EdwardsPoint};
use monero_primitives::{INV_EIGHT, Commitment, keccak256_to_scalar};
use crate::{
batch_verifier::BulletproofsPlusBatchVerifier,
core::{MAX_M, N, multiexp, multiexp_vartime},
plus::{
ScalarVector, PointVector, GeneratorsList, BpPlusGenerators,
transcript::*,
weighted_inner_product::{WipStatement, WipWitness, WipProof},
padded_pow_of_2, u64_decompose,
},
};
// Figure 3 of the Bulletproofs+ Paper
#[derive(Clone, Debug)]
pub(crate) struct AggregateRangeStatement {
generators: BpPlusGenerators,
V: Vec<EdwardsPoint>,
}
impl Zeroize for AggregateRangeStatement {
fn zeroize(&mut self) {
self.V.zeroize();
}
}
#[derive(Clone, Debug, Zeroize, ZeroizeOnDrop)]
pub(crate) struct AggregateRangeWitness(Vec<Commitment>);
impl AggregateRangeWitness {
pub(crate) fn new(commitments: Vec<Commitment>) -> Option<Self> {
if commitments.is_empty() || (commitments.len() > MAX_M) {
return None;
}
Some(AggregateRangeWitness(commitments))
}
}
/// Internal structure representing a Bulletproof+, as used in Monero.
#[derive(Clone, PartialEq, Eq, Debug, Zeroize)]
pub struct AggregateRangeProof {
pub(crate) A: EdwardsPoint,
pub(crate) wip: WipProof,
}
struct AHatComputation {
y: Scalar,
d_descending_y_plus_z: ScalarVector,
y_mn_plus_one: Scalar,
z: Scalar,
z_pow: ScalarVector,
A_hat: EdwardsPoint,
}
impl AggregateRangeStatement {
pub(crate) fn new(V: Vec<EdwardsPoint>) -> Option<Self> {
if V.is_empty() || (V.len() > MAX_M) {
return None;
}
Some(Self { generators: BpPlusGenerators::new(), V })
}
fn transcript_A(transcript: &mut Scalar, A: EdwardsPoint) -> (Scalar, Scalar) {
let y = keccak256_to_scalar(
[transcript.to_bytes().as_ref(), A.compress().to_bytes().as_ref()].concat(),
);
let z = keccak256_to_scalar(y.to_bytes().as_ref());
*transcript = z;
(y, z)
}
fn d_j(j: usize, m: usize) -> ScalarVector {
let mut d_j = Vec::with_capacity(m * N);
for _ in 0 .. (j - 1) * N {
d_j.push(Scalar::ZERO);
}
d_j.append(&mut ScalarVector::powers(Scalar::from(2u8), N).0);
for _ in 0 .. (m - j) * N {
d_j.push(Scalar::ZERO);
}
ScalarVector(d_j)
}
fn compute_A_hat(
mut V: PointVector,
generators: &BpPlusGenerators,
transcript: &mut Scalar,
mut A: EdwardsPoint,
) -> AHatComputation {
let (y, z) = Self::transcript_A(transcript, A);
A = A.mul_by_cofactor();
while V.len() < padded_pow_of_2(V.len()) {
V.0.push(EdwardsPoint::identity());
}
let mn = V.len() * N;
// 2, 4, 6, 8... powers of z, of length equivalent to the amount of commitments
let mut z_pow = Vec::with_capacity(V.len());
// z**2
z_pow.push(z * z);
let mut d = ScalarVector::new(mn);
for j in 1 ..= V.len() {
z_pow.push(*z_pow.last().unwrap() * z_pow[0]);
d = d + &(Self::d_j(j, V.len()) * (z_pow[j - 1]));
}
let mut ascending_y = ScalarVector(vec![y]);
for i in 1 .. d.len() {
ascending_y.0.push(ascending_y[i - 1] * y);
}
let y_pows = ascending_y.clone().sum();
let mut descending_y = ascending_y.clone();
descending_y.0.reverse();
let d_descending_y = d.clone() * &descending_y;
let d_descending_y_plus_z = d_descending_y + z;
let y_mn_plus_one = descending_y[0] * y;
let mut commitment_accum = EdwardsPoint::identity();
for (j, commitment) in V.0.iter().enumerate() {
commitment_accum += *commitment * z_pow[j];
}
let neg_z = -z;
let mut A_terms = Vec::with_capacity((generators.len() * 2) + 2);
for (i, d_y_z) in d_descending_y_plus_z.0.iter().enumerate() {
A_terms.push((neg_z, generators.generator(GeneratorsList::GBold, i)));
A_terms.push((*d_y_z, generators.generator(GeneratorsList::HBold, i)));
}
A_terms.push((y_mn_plus_one, commitment_accum));
A_terms.push((
((y_pows * z) - (d.sum() * y_mn_plus_one * z) - (y_pows * (z * z))),
BpPlusGenerators::g(),
));
AHatComputation {
y,
d_descending_y_plus_z,
y_mn_plus_one,
z,
z_pow: ScalarVector(z_pow),
A_hat: A + multiexp_vartime(&A_terms),
}
}
pub(crate) fn prove<R: RngCore + CryptoRng>(
self,
rng: &mut R,
witness: &AggregateRangeWitness,
) -> Option<AggregateRangeProof> {
// Check for consistency with the witness
if self.V.len() != witness.0.len() {
return None;
}
for (commitment, witness) in self.V.iter().zip(witness.0.iter()) {
if witness.calculate() != *commitment {
return None;
}
}
let Self { generators, V } = self;
// Monero expects all of these points to be torsion-free
// Generally, for Bulletproofs, it sends points * INV_EIGHT and then performs a torsion clear
// by multiplying by 8
// This also restores the original value due to the preprocessing
// Commitments aren't transmitted INV_EIGHT though, so this multiplies by INV_EIGHT to enable
// clearing its cofactor without mutating the value
// For some reason, these values are transcripted * INV_EIGHT, not as transmitted
let V = V.into_iter().map(|V| V * INV_EIGHT()).collect::<Vec<_>>();
let mut transcript = initial_transcript(V.iter());
let mut V = V.iter().map(EdwardsPoint::mul_by_cofactor).collect::<Vec<_>>();
// Pad V
while V.len() < padded_pow_of_2(V.len()) {
V.push(EdwardsPoint::identity());
}
let generators = generators.reduce(V.len() * N);
let mut d_js = Vec::with_capacity(V.len());
let mut a_l = ScalarVector(Vec::with_capacity(V.len() * N));
for j in 1 ..= V.len() {
d_js.push(Self::d_j(j, V.len()));
#[allow(clippy::map_unwrap_or)]
a_l.0.append(
&mut u64_decompose(
*witness.0.get(j - 1).map(|commitment| &commitment.amount).unwrap_or(&0),
)
.0,
);
}
let a_r = a_l.clone() - Scalar::ONE;
let alpha = Scalar::random(&mut *rng);
let mut A_terms = Vec::with_capacity((generators.len() * 2) + 1);
for (i, a_l) in a_l.0.iter().enumerate() {
A_terms.push((*a_l, generators.generator(GeneratorsList::GBold, i)));
}
for (i, a_r) in a_r.0.iter().enumerate() {
A_terms.push((*a_r, generators.generator(GeneratorsList::HBold, i)));
}
A_terms.push((alpha, BpPlusGenerators::h()));
let mut A = multiexp(&A_terms);
A_terms.zeroize();
// Multiply by INV_EIGHT per earlier commentary
A *= INV_EIGHT();
let AHatComputation { y, d_descending_y_plus_z, y_mn_plus_one, z, z_pow, A_hat } =
Self::compute_A_hat(PointVector(V), &generators, &mut transcript, A);
let a_l = a_l - z;
let a_r = a_r + &d_descending_y_plus_z;
let mut alpha = alpha;
for j in 1 ..= witness.0.len() {
alpha += z_pow[j - 1] * witness.0[j - 1].mask * y_mn_plus_one;
}
Some(AggregateRangeProof {
A,
wip: WipStatement::new(generators, A_hat, y)
.prove(rng, transcript, &Zeroizing::new(WipWitness::new(a_l, a_r, alpha).unwrap()))
.unwrap(),
})
}
pub(crate) fn verify<R: RngCore + CryptoRng>(
self,
rng: &mut R,
verifier: &mut BulletproofsPlusBatchVerifier,
proof: AggregateRangeProof,
) -> bool {
let Self { generators, V } = self;
let V = V.into_iter().map(|V| V * INV_EIGHT()).collect::<Vec<_>>();
let mut transcript = initial_transcript(V.iter());
let V = V.iter().map(EdwardsPoint::mul_by_cofactor).collect::<Vec<_>>();
let generators = generators.reduce(V.len() * N);
let AHatComputation { y, A_hat, .. } =
Self::compute_A_hat(PointVector(V), &generators, &mut transcript, proof.A);
WipStatement::new(generators, A_hat, y).verify(rng, verifier, transcript, proof.wip)
}
}

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@@ -0,0 +1,85 @@
#![allow(non_snake_case)]
use std_shims::sync::OnceLock;
use curve25519_dalek::{constants::ED25519_BASEPOINT_POINT, scalar::Scalar, edwards::EdwardsPoint};
use monero_generators::{H, Generators};
pub(crate) use crate::scalar_vector::ScalarVector;
mod point_vector;
pub(crate) use point_vector::PointVector;
pub(crate) mod transcript;
pub(crate) mod weighted_inner_product;
pub(crate) use weighted_inner_product::*;
pub(crate) mod aggregate_range_proof;
pub(crate) use aggregate_range_proof::*;
pub(crate) fn padded_pow_of_2(i: usize) -> usize {
let mut next_pow_of_2 = 1;
while next_pow_of_2 < i {
next_pow_of_2 <<= 1;
}
next_pow_of_2
}
#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
pub(crate) enum GeneratorsList {
GBold,
HBold,
}
// TODO: Table these
#[derive(Clone, Debug)]
pub(crate) struct BpPlusGenerators {
g_bold: &'static [EdwardsPoint],
h_bold: &'static [EdwardsPoint],
}
include!(concat!(env!("OUT_DIR"), "/generators_plus.rs"));
impl BpPlusGenerators {
#[allow(clippy::new_without_default)]
pub(crate) fn new() -> Self {
let gens = GENERATORS();
BpPlusGenerators { g_bold: &gens.G, h_bold: &gens.H }
}
pub(crate) fn len(&self) -> usize {
self.g_bold.len()
}
pub(crate) fn g() -> EdwardsPoint {
H()
}
pub(crate) fn h() -> EdwardsPoint {
ED25519_BASEPOINT_POINT
}
pub(crate) fn generator(&self, list: GeneratorsList, i: usize) -> EdwardsPoint {
match list {
GeneratorsList::GBold => self.g_bold[i],
GeneratorsList::HBold => self.h_bold[i],
}
}
pub(crate) fn reduce(&self, generators: usize) -> Self {
// Round to the nearest power of 2
let generators = padded_pow_of_2(generators);
assert!(generators <= self.g_bold.len());
BpPlusGenerators { g_bold: &self.g_bold[.. generators], h_bold: &self.h_bold[.. generators] }
}
}
// Returns the little-endian decomposition.
fn u64_decompose(value: u64) -> ScalarVector {
let mut bits = ScalarVector::new(64);
for bit in 0 .. 64 {
bits[bit] = Scalar::from((value >> bit) & 1);
}
bits
}

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@@ -0,0 +1,48 @@
use core::ops::{Index, IndexMut};
use std_shims::vec::Vec;
use zeroize::{Zeroize, ZeroizeOnDrop};
use curve25519_dalek::edwards::EdwardsPoint;
#[cfg(test)]
use crate::{core::multiexp, plus::ScalarVector};
#[derive(Clone, PartialEq, Eq, Debug, Zeroize, ZeroizeOnDrop)]
pub(crate) struct PointVector(pub(crate) Vec<EdwardsPoint>);
impl Index<usize> for PointVector {
type Output = EdwardsPoint;
fn index(&self, index: usize) -> &EdwardsPoint {
&self.0[index]
}
}
impl IndexMut<usize> for PointVector {
fn index_mut(&mut self, index: usize) -> &mut EdwardsPoint {
&mut self.0[index]
}
}
impl PointVector {
#[cfg(test)]
pub(crate) fn multiexp(&self, vector: &ScalarVector) -> EdwardsPoint {
debug_assert_eq!(self.len(), vector.len());
let mut res = Vec::with_capacity(self.len());
for (point, scalar) in self.0.iter().copied().zip(vector.0.iter().copied()) {
res.push((scalar, point));
}
multiexp(&res)
}
pub(crate) fn len(&self) -> usize {
self.0.len()
}
pub(crate) fn split(mut self) -> (Self, Self) {
debug_assert!(self.len() > 1);
let r = self.0.split_off(self.0.len() / 2);
debug_assert_eq!(self.len(), r.len());
(self, PointVector(r))
}
}

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@@ -0,0 +1,20 @@
use std_shims::{sync::OnceLock, vec::Vec};
use curve25519_dalek::{scalar::Scalar, edwards::EdwardsPoint};
use monero_generators::hash_to_point;
use monero_primitives::{keccak256, keccak256_to_scalar};
// Monero starts BP+ transcripts with the following constant.
static TRANSCRIPT_CELL: OnceLock<[u8; 32]> = OnceLock::new();
pub(crate) fn TRANSCRIPT() -> [u8; 32] {
// Why this uses a hash_to_point is completely unknown.
*TRANSCRIPT_CELL
.get_or_init(|| hash_to_point(keccak256(b"bulletproof_plus_transcript")).compress().to_bytes())
}
pub(crate) fn initial_transcript(commitments: core::slice::Iter<'_, EdwardsPoint>) -> Scalar {
let commitments_hash =
keccak256_to_scalar(commitments.flat_map(|V| V.compress().to_bytes()).collect::<Vec<_>>());
keccak256_to_scalar([TRANSCRIPT().as_ref(), &commitments_hash.to_bytes()].concat())
}

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@@ -0,0 +1,443 @@
use std_shims::vec::Vec;
use rand_core::{RngCore, CryptoRng};
use zeroize::{Zeroize, ZeroizeOnDrop};
use curve25519_dalek::{scalar::Scalar, edwards::EdwardsPoint};
use monero_primitives::{INV_EIGHT, keccak256_to_scalar};
use crate::{
core::{multiexp, multiexp_vartime},
batch_verifier::BulletproofsPlusBatchVerifier,
plus::{ScalarVector, PointVector, GeneratorsList, BpPlusGenerators, padded_pow_of_2},
};
// Figure 1 of the Bulletproofs+ paper
#[derive(Clone, Debug)]
pub(crate) struct WipStatement {
generators: BpPlusGenerators,
P: EdwardsPoint,
y: ScalarVector,
}
impl Zeroize for WipStatement {
fn zeroize(&mut self) {
self.P.zeroize();
self.y.zeroize();
}
}
#[derive(Clone, Debug, Zeroize, ZeroizeOnDrop)]
pub(crate) struct WipWitness {
a: ScalarVector,
b: ScalarVector,
alpha: Scalar,
}
impl WipWitness {
pub(crate) fn new(mut a: ScalarVector, mut b: ScalarVector, alpha: Scalar) -> Option<Self> {
if a.0.is_empty() || (a.len() != b.len()) {
return None;
}
// Pad to the nearest power of 2
let missing = padded_pow_of_2(a.len()) - a.len();
a.0.reserve(missing);
b.0.reserve(missing);
for _ in 0 .. missing {
a.0.push(Scalar::ZERO);
b.0.push(Scalar::ZERO);
}
Some(Self { a, b, alpha })
}
}
#[derive(Clone, PartialEq, Eq, Debug, Zeroize)]
pub(crate) struct WipProof {
pub(crate) L: Vec<EdwardsPoint>,
pub(crate) R: Vec<EdwardsPoint>,
pub(crate) A: EdwardsPoint,
pub(crate) B: EdwardsPoint,
pub(crate) r_answer: Scalar,
pub(crate) s_answer: Scalar,
pub(crate) delta_answer: Scalar,
}
impl WipStatement {
pub(crate) fn new(generators: BpPlusGenerators, P: EdwardsPoint, y: Scalar) -> Self {
debug_assert_eq!(generators.len(), padded_pow_of_2(generators.len()));
// y ** n
let mut y_vec = ScalarVector::new(generators.len());
y_vec[0] = y;
for i in 1 .. y_vec.len() {
y_vec[i] = y_vec[i - 1] * y;
}
Self { generators, P, y: y_vec }
}
fn transcript_L_R(transcript: &mut Scalar, L: EdwardsPoint, R: EdwardsPoint) -> Scalar {
let e = keccak256_to_scalar(
[
transcript.to_bytes().as_ref(),
L.compress().to_bytes().as_ref(),
R.compress().to_bytes().as_ref(),
]
.concat(),
);
*transcript = e;
e
}
fn transcript_A_B(transcript: &mut Scalar, A: EdwardsPoint, B: EdwardsPoint) -> Scalar {
let e = keccak256_to_scalar(
[
transcript.to_bytes().as_ref(),
A.compress().to_bytes().as_ref(),
B.compress().to_bytes().as_ref(),
]
.concat(),
);
*transcript = e;
e
}
// Prover's variant of the shared code block to calculate G/H/P when n > 1
// Returns each permutation of G/H since the prover needs to do operation on each permutation
// P is dropped as it's unused in the prover's path
// TODO: It'd still probably be faster to keep in terms of the original generators, both between
// the reduced amount of group operations and the potential tabling of the generators under
// multiexp
#[allow(clippy::too_many_arguments)]
fn next_G_H(
transcript: &mut Scalar,
mut g_bold1: PointVector,
mut g_bold2: PointVector,
mut h_bold1: PointVector,
mut h_bold2: PointVector,
L: EdwardsPoint,
R: EdwardsPoint,
y_inv_n_hat: Scalar,
) -> (Scalar, Scalar, Scalar, Scalar, PointVector, PointVector) {
debug_assert_eq!(g_bold1.len(), g_bold2.len());
debug_assert_eq!(h_bold1.len(), h_bold2.len());
debug_assert_eq!(g_bold1.len(), h_bold1.len());
let e = Self::transcript_L_R(transcript, L, R);
let inv_e = e.invert();
// This vartime is safe as all of these arguments are public
let mut new_g_bold = Vec::with_capacity(g_bold1.len());
let e_y_inv = e * y_inv_n_hat;
for g_bold in g_bold1.0.drain(..).zip(g_bold2.0.drain(..)) {
new_g_bold.push(multiexp_vartime(&[(inv_e, g_bold.0), (e_y_inv, g_bold.1)]));
}
let mut new_h_bold = Vec::with_capacity(h_bold1.len());
for h_bold in h_bold1.0.drain(..).zip(h_bold2.0.drain(..)) {
new_h_bold.push(multiexp_vartime(&[(e, h_bold.0), (inv_e, h_bold.1)]));
}
let e_square = e * e;
let inv_e_square = inv_e * inv_e;
(e, inv_e, e_square, inv_e_square, PointVector(new_g_bold), PointVector(new_h_bold))
}
/*
This has room for optimization worth investigating further. It currently takes
an iterative approach. It can be optimized further via divide and conquer.
Assume there are 4 challenges.
Iterative approach (current):
1. Do the optimal multiplications across challenge column 0 and 1.
2. Do the optimal multiplications across that result and column 2.
3. Do the optimal multiplications across that result and column 3.
Divide and conquer (worth investigating further):
1. Do the optimal multiplications across challenge column 0 and 1.
2. Do the optimal multiplications across challenge column 2 and 3.
3. Multiply both results together.
When there are 4 challenges (n=16), the iterative approach does 28 multiplications
versus divide and conquer's 24.
*/
fn challenge_products(challenges: &[(Scalar, Scalar)]) -> Vec<Scalar> {
let mut products = vec![Scalar::ONE; 1 << challenges.len()];
if !challenges.is_empty() {
products[0] = challenges[0].1;
products[1] = challenges[0].0;
for (j, challenge) in challenges.iter().enumerate().skip(1) {
let mut slots = (1 << (j + 1)) - 1;
while slots > 0 {
products[slots] = products[slots / 2] * challenge.0;
products[slots - 1] = products[slots / 2] * challenge.1;
slots = slots.saturating_sub(2);
}
}
// Sanity check since if the above failed to populate, it'd be critical
for product in &products {
debug_assert!(*product != Scalar::ZERO);
}
}
products
}
pub(crate) fn prove<R: RngCore + CryptoRng>(
self,
rng: &mut R,
mut transcript: Scalar,
witness: &WipWitness,
) -> Option<WipProof> {
let WipStatement { generators, P, mut y } = self;
#[cfg(not(debug_assertions))]
let _ = P;
if generators.len() != witness.a.len() {
return None;
}
let (g, h) = (BpPlusGenerators::g(), BpPlusGenerators::h());
let mut g_bold = vec![];
let mut h_bold = vec![];
for i in 0 .. generators.len() {
g_bold.push(generators.generator(GeneratorsList::GBold, i));
h_bold.push(generators.generator(GeneratorsList::HBold, i));
}
let mut g_bold = PointVector(g_bold);
let mut h_bold = PointVector(h_bold);
// Check P has the expected relationship
#[cfg(debug_assertions)]
{
let mut P_terms = witness
.a
.0
.iter()
.copied()
.zip(g_bold.0.iter().copied())
.chain(witness.b.0.iter().copied().zip(h_bold.0.iter().copied()))
.collect::<Vec<_>>();
P_terms.push((witness.a.clone().weighted_inner_product(&witness.b, &y), g));
P_terms.push((witness.alpha, h));
debug_assert_eq!(multiexp(&P_terms), P);
P_terms.zeroize();
}
let mut a = witness.a.clone();
let mut b = witness.b.clone();
let mut alpha = witness.alpha;
// From here on, g_bold.len() is used as n
debug_assert_eq!(g_bold.len(), a.len());
let mut L_vec = vec![];
let mut R_vec = vec![];
// else n > 1 case from figure 1
while g_bold.len() > 1 {
let (a1, a2) = a.clone().split();
let (b1, b2) = b.clone().split();
let (g_bold1, g_bold2) = g_bold.split();
let (h_bold1, h_bold2) = h_bold.split();
let n_hat = g_bold1.len();
debug_assert_eq!(a1.len(), n_hat);
debug_assert_eq!(a2.len(), n_hat);
debug_assert_eq!(b1.len(), n_hat);
debug_assert_eq!(b2.len(), n_hat);
debug_assert_eq!(g_bold1.len(), n_hat);
debug_assert_eq!(g_bold2.len(), n_hat);
debug_assert_eq!(h_bold1.len(), n_hat);
debug_assert_eq!(h_bold2.len(), n_hat);
let y_n_hat = y[n_hat - 1];
y.0.truncate(n_hat);
let d_l = Scalar::random(&mut *rng);
let d_r = Scalar::random(&mut *rng);
let c_l = a1.clone().weighted_inner_product(&b2, &y);
let c_r = (a2.clone() * y_n_hat).weighted_inner_product(&b1, &y);
// TODO: Calculate these with a batch inversion
let y_inv_n_hat = y_n_hat.invert();
let mut L_terms = (a1.clone() * y_inv_n_hat)
.0
.drain(..)
.zip(g_bold2.0.iter().copied())
.chain(b2.0.iter().copied().zip(h_bold1.0.iter().copied()))
.collect::<Vec<_>>();
L_terms.push((c_l, g));
L_terms.push((d_l, h));
let L = multiexp(&L_terms) * INV_EIGHT();
L_vec.push(L);
L_terms.zeroize();
let mut R_terms = (a2.clone() * y_n_hat)
.0
.drain(..)
.zip(g_bold1.0.iter().copied())
.chain(b1.0.iter().copied().zip(h_bold2.0.iter().copied()))
.collect::<Vec<_>>();
R_terms.push((c_r, g));
R_terms.push((d_r, h));
let R = multiexp(&R_terms) * INV_EIGHT();
R_vec.push(R);
R_terms.zeroize();
let (e, inv_e, e_square, inv_e_square);
(e, inv_e, e_square, inv_e_square, g_bold, h_bold) =
Self::next_G_H(&mut transcript, g_bold1, g_bold2, h_bold1, h_bold2, L, R, y_inv_n_hat);
a = (a1 * e) + &(a2 * (y_n_hat * inv_e));
b = (b1 * inv_e) + &(b2 * e);
alpha += (d_l * e_square) + (d_r * inv_e_square);
debug_assert_eq!(g_bold.len(), a.len());
debug_assert_eq!(g_bold.len(), h_bold.len());
debug_assert_eq!(g_bold.len(), b.len());
}
// n == 1 case from figure 1
debug_assert_eq!(g_bold.len(), 1);
debug_assert_eq!(h_bold.len(), 1);
debug_assert_eq!(a.len(), 1);
debug_assert_eq!(b.len(), 1);
let r = Scalar::random(&mut *rng);
let s = Scalar::random(&mut *rng);
let delta = Scalar::random(&mut *rng);
let eta = Scalar::random(&mut *rng);
let ry = r * y[0];
let mut A_terms =
vec![(r, g_bold[0]), (s, h_bold[0]), ((ry * b[0]) + (s * y[0] * a[0]), g), (delta, h)];
let A = multiexp(&A_terms) * INV_EIGHT();
A_terms.zeroize();
let mut B_terms = vec![(ry * s, g), (eta, h)];
let B = multiexp(&B_terms) * INV_EIGHT();
B_terms.zeroize();
let e = Self::transcript_A_B(&mut transcript, A, B);
let r_answer = r + (a[0] * e);
let s_answer = s + (b[0] * e);
let delta_answer = eta + (delta * e) + (alpha * (e * e));
Some(WipProof { L: L_vec, R: R_vec, A, B, r_answer, s_answer, delta_answer })
}
pub(crate) fn verify<R: RngCore + CryptoRng>(
self,
rng: &mut R,
verifier: &mut BulletproofsPlusBatchVerifier,
mut transcript: Scalar,
mut proof: WipProof,
) -> bool {
let verifier_weight = Scalar::random(rng);
let WipStatement { generators, P, y } = self;
// Verify the L/R lengths
{
let mut lr_len = 0;
while (1 << lr_len) < generators.len() {
lr_len += 1;
}
if (proof.L.len() != lr_len) ||
(proof.R.len() != lr_len) ||
(generators.len() != (1 << lr_len))
{
return false;
}
}
let inv_y = {
let inv_y = y[0].invert();
let mut res = Vec::with_capacity(y.len());
res.push(inv_y);
while res.len() < y.len() {
res.push(inv_y * res.last().unwrap());
}
res
};
let mut e_is = Vec::with_capacity(proof.L.len());
for (L, R) in proof.L.iter_mut().zip(proof.R.iter_mut()) {
e_is.push(Self::transcript_L_R(&mut transcript, *L, *R));
*L = L.mul_by_cofactor();
*R = R.mul_by_cofactor();
}
let e = Self::transcript_A_B(&mut transcript, proof.A, proof.B);
proof.A = proof.A.mul_by_cofactor();
proof.B = proof.B.mul_by_cofactor();
let neg_e_square = verifier_weight * -(e * e);
verifier.0.other.push((neg_e_square, P));
let mut challenges = Vec::with_capacity(proof.L.len());
let product_cache = {
let mut inv_e_is = e_is.clone();
Scalar::batch_invert(&mut inv_e_is);
debug_assert_eq!(e_is.len(), inv_e_is.len());
debug_assert_eq!(e_is.len(), proof.L.len());
debug_assert_eq!(e_is.len(), proof.R.len());
for ((e_i, inv_e_i), (L, R)) in
e_is.drain(..).zip(inv_e_is.drain(..)).zip(proof.L.iter().zip(proof.R.iter()))
{
debug_assert_eq!(e_i.invert(), inv_e_i);
challenges.push((e_i, inv_e_i));
let e_i_square = e_i * e_i;
let inv_e_i_square = inv_e_i * inv_e_i;
verifier.0.other.push((neg_e_square * e_i_square, *L));
verifier.0.other.push((neg_e_square * inv_e_i_square, *R));
}
Self::challenge_products(&challenges)
};
while verifier.0.g_bold.len() < generators.len() {
verifier.0.g_bold.push(Scalar::ZERO);
}
while verifier.0.h_bold.len() < generators.len() {
verifier.0.h_bold.push(Scalar::ZERO);
}
let re = proof.r_answer * e;
for i in 0 .. generators.len() {
let mut scalar = product_cache[i] * re;
if i > 0 {
scalar *= inv_y[i - 1];
}
verifier.0.g_bold[i] += verifier_weight * scalar;
}
let se = proof.s_answer * e;
for i in 0 .. generators.len() {
verifier.0.h_bold[i] += verifier_weight * (se * product_cache[product_cache.len() - 1 - i]);
}
verifier.0.other.push((verifier_weight * -e, proof.A));
verifier.0.g += verifier_weight * (proof.r_answer * y[0] * proof.s_answer);
verifier.0.h += verifier_weight * proof.delta_answer;
verifier.0.other.push((-verifier_weight, proof.B));
true
}
}

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use core::{
borrow::Borrow,
ops::{Index, IndexMut, Add, Sub, Mul},
};
use std_shims::vec::Vec;
use zeroize::{Zeroize, ZeroizeOnDrop};
use curve25519_dalek::{scalar::Scalar, edwards::EdwardsPoint};
use crate::core::multiexp;
#[derive(Clone, PartialEq, Eq, Debug, Zeroize, ZeroizeOnDrop)]
pub(crate) struct ScalarVector(pub(crate) Vec<Scalar>);
impl Index<usize> for ScalarVector {
type Output = Scalar;
fn index(&self, index: usize) -> &Scalar {
&self.0[index]
}
}
impl IndexMut<usize> for ScalarVector {
fn index_mut(&mut self, index: usize) -> &mut Scalar {
&mut self.0[index]
}
}
impl<S: Borrow<Scalar>> Add<S> for ScalarVector {
type Output = ScalarVector;
fn add(mut self, scalar: S) -> ScalarVector {
for s in &mut self.0 {
*s += scalar.borrow();
}
self
}
}
impl<S: Borrow<Scalar>> Sub<S> for ScalarVector {
type Output = ScalarVector;
fn sub(mut self, scalar: S) -> ScalarVector {
for s in &mut self.0 {
*s -= scalar.borrow();
}
self
}
}
impl<S: Borrow<Scalar>> Mul<S> for ScalarVector {
type Output = ScalarVector;
fn mul(mut self, scalar: S) -> ScalarVector {
for s in &mut self.0 {
*s *= scalar.borrow();
}
self
}
}
impl Add<&ScalarVector> for ScalarVector {
type Output = ScalarVector;
fn add(mut self, other: &ScalarVector) -> ScalarVector {
debug_assert_eq!(self.len(), other.len());
for (s, o) in self.0.iter_mut().zip(other.0.iter()) {
*s += o;
}
self
}
}
impl Sub<&ScalarVector> for ScalarVector {
type Output = ScalarVector;
fn sub(mut self, other: &ScalarVector) -> ScalarVector {
debug_assert_eq!(self.len(), other.len());
for (s, o) in self.0.iter_mut().zip(other.0.iter()) {
*s -= o;
}
self
}
}
impl Mul<&ScalarVector> for ScalarVector {
type Output = ScalarVector;
fn mul(mut self, other: &ScalarVector) -> ScalarVector {
debug_assert_eq!(self.len(), other.len());
for (s, o) in self.0.iter_mut().zip(other.0.iter()) {
*s *= o;
}
self
}
}
impl Mul<&[EdwardsPoint]> for &ScalarVector {
type Output = EdwardsPoint;
fn mul(self, b: &[EdwardsPoint]) -> EdwardsPoint {
debug_assert_eq!(self.len(), b.len());
let mut multiexp_args = self.0.iter().copied().zip(b.iter().copied()).collect::<Vec<_>>();
let res = multiexp(&multiexp_args);
multiexp_args.zeroize();
res
}
}
impl ScalarVector {
pub(crate) fn new(len: usize) -> Self {
ScalarVector(vec![Scalar::ZERO; len])
}
pub(crate) fn powers(x: Scalar, len: usize) -> Self {
debug_assert!(len != 0);
let mut res = Vec::with_capacity(len);
res.push(Scalar::ONE);
res.push(x);
for i in 2 .. len {
res.push(res[i - 1] * x);
}
res.truncate(len);
ScalarVector(res)
}
pub(crate) fn len(&self) -> usize {
self.0.len()
}
pub(crate) fn sum(mut self) -> Scalar {
self.0.drain(..).sum()
}
pub(crate) fn inner_product(self, vector: &Self) -> Scalar {
(self * vector).sum()
}
pub(crate) fn weighted_inner_product(self, vector: &Self, y: &Self) -> Scalar {
(self * vector * y).sum()
}
pub(crate) fn split(mut self) -> (Self, Self) {
debug_assert!(self.len() > 1);
let r = self.0.split_off(self.0.len() / 2);
debug_assert_eq!(self.len(), r.len());
(self, ScalarVector(r))
}
}

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@@ -0,0 +1,105 @@
use hex_literal::hex;
use rand_core::OsRng;
use curve25519_dalek::scalar::Scalar;
use monero_io::decompress_point;
use monero_primitives::Commitment;
use crate::{batch_verifier::BatchVerifier, original::OriginalStruct, Bulletproof, BulletproofError};
mod plus;
#[test]
fn bulletproofs_vector() {
let scalar = |scalar| Scalar::from_canonical_bytes(scalar).unwrap();
let point = |point| decompress_point(point).unwrap();
// Generated from Monero
assert!(Bulletproof::Original(OriginalStruct {
A: point(hex!("ef32c0b9551b804decdcb107eb22aa715b7ce259bf3c5cac20e24dfa6b28ac71")),
S: point(hex!("e1285960861783574ee2b689ae53622834eb0b035d6943103f960cd23e063fa0")),
T1: point(hex!("4ea07735f184ba159d0e0eb662bac8cde3eb7d39f31e567b0fbda3aa23fe5620")),
T2: point(hex!("b8390aa4b60b255630d40e592f55ec6b7ab5e3a96bfcdcd6f1cd1d2fc95f441e")),
tau_x: scalar(hex!("5957dba8ea9afb23d6e81cc048a92f2d502c10c749dc1b2bd148ae8d41ec7107")),
mu: scalar(hex!("923023b234c2e64774b820b4961f7181f6c1dc152c438643e5a25b0bf271bc02")),
L: vec![
point(hex!("c45f656316b9ebf9d357fb6a9f85b5f09e0b991dd50a6e0ae9b02de3946c9d99")),
point(hex!("9304d2bf0f27183a2acc58cc755a0348da11bd345485fda41b872fee89e72aac")),
point(hex!("1bb8b71925d155dd9569f64129ea049d6149fdc4e7a42a86d9478801d922129b")),
point(hex!("5756a7bf887aa72b9a952f92f47182122e7b19d89e5dd434c747492b00e1c6b7")),
point(hex!("6e497c910d102592830555356af5ff8340e8d141e3fb60ea24cfa587e964f07d")),
point(hex!("f4fa3898e7b08e039183d444f3d55040f3c790ed806cb314de49f3068bdbb218")),
point(hex!("0bbc37597c3ead517a3841e159c8b7b79a5ceaee24b2a9a20350127aab428713")),
],
R: vec![
point(hex!("609420ba1702781692e84accfd225adb3d077aedc3cf8125563400466b52dbd9")),
point(hex!("fb4e1d079e7a2b0ec14f7e2a3943bf50b6d60bc346a54fcf562fb234b342abf8")),
point(hex!("6ae3ac97289c48ce95b9c557289e82a34932055f7f5e32720139824fe81b12e5")),
point(hex!("d071cc2ffbdab2d840326ad15f68c01da6482271cae3cf644670d1632f29a15c")),
point(hex!("e52a1754b95e1060589ba7ce0c43d0060820ebfc0d49dc52884bc3c65ad18af5")),
point(hex!("41573b06140108539957df71aceb4b1816d2409ce896659aa5c86f037ca5e851")),
point(hex!("a65970b2cc3c7b08b2b5b739dbc8e71e646783c41c625e2a5b1535e3d2e0f742")),
],
a: scalar(hex!("0077c5383dea44d3cd1bc74849376bd60679612dc4b945255822457fa0c0a209")),
b: scalar(hex!("fe80cf5756473482581e1d38644007793ddc66fdeb9404ec1689a907e4863302")),
t: scalar(hex!("40dfb08e09249040df997851db311bd6827c26e87d6f0f332c55be8eef10e603"))
})
.verify(
&mut OsRng,
&[
// For some reason, these vectors are * INV_EIGHT
point(hex!("8e8f23f315edae4f6c2f948d9a861e0ae32d356b933cd11d2f0e031ac744c41f"))
.mul_by_cofactor(),
point(hex!("2829cbd025aa54cd6e1b59a032564f22f0b2e5627f7f2c4297f90da438b5510f"))
.mul_by_cofactor(),
]
));
}
macro_rules! bulletproofs_tests {
($name: ident, $max: ident, $plus: literal) => {
#[test]
fn $name() {
// Create Bulletproofs for all possible output quantities
let mut verifier = BatchVerifier::new();
for i in 1 ..= 16 {
let commitments = (1 ..= i)
.map(|i| Commitment::new(Scalar::random(&mut OsRng), u64::try_from(i).unwrap()))
.collect::<Vec<_>>();
let bp = if $plus {
Bulletproof::prove_plus(&mut OsRng, commitments.clone()).unwrap()
} else {
Bulletproof::prove(&mut OsRng, &commitments).unwrap()
};
let commitments = commitments.iter().map(Commitment::calculate).collect::<Vec<_>>();
assert!(bp.verify(&mut OsRng, &commitments));
assert!(bp.batch_verify(&mut OsRng, &mut verifier, &commitments));
}
assert!(verifier.verify());
}
#[test]
fn $max() {
// Check Bulletproofs errors if we try to prove for too many outputs
let mut commitments = vec![];
for _ in 0 .. 17 {
commitments.push(Commitment::new(Scalar::ZERO, 0));
}
assert_eq!(
(if $plus {
Bulletproof::prove_plus(&mut OsRng, commitments)
} else {
Bulletproof::prove(&mut OsRng, &commitments)
})
.unwrap_err(),
BulletproofError::TooManyCommitments,
);
}
};
}
bulletproofs_tests!(bulletproofs, bulletproofs_max, false);
bulletproofs_tests!(bulletproofs_plus, bulletproofs_plus_max, true);

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use rand_core::{RngCore, OsRng};
use curve25519_dalek::Scalar;
use monero_primitives::Commitment;
use crate::{
batch_verifier::BulletproofsPlusBatchVerifier,
plus::aggregate_range_proof::{AggregateRangeStatement, AggregateRangeWitness},
};
#[test]
fn test_aggregate_range_proof() {
let mut verifier = BulletproofsPlusBatchVerifier::default();
for m in 1 ..= 16 {
let mut commitments = vec![];
for _ in 0 .. m {
commitments.push(Commitment::new(Scalar::random(&mut OsRng), OsRng.next_u64()));
}
let commitment_points = commitments.iter().map(Commitment::calculate).collect();
let statement = AggregateRangeStatement::new(commitment_points).unwrap();
let witness = AggregateRangeWitness::new(commitments).unwrap();
let proof = statement.clone().prove(&mut OsRng, &witness).unwrap();
statement.verify(&mut OsRng, &mut verifier, proof);
}
assert!(verifier.verify());
}

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@@ -0,0 +1,4 @@
#[cfg(test)]
mod weighted_inner_product;
#[cfg(test)]
mod aggregate_range_proof;

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@@ -0,0 +1,82 @@
// The inner product relation is P = sum(g_bold * a, h_bold * b, g * (a * y * b), h * alpha)
use rand_core::OsRng;
use curve25519_dalek::{traits::Identity, scalar::Scalar, edwards::EdwardsPoint};
use crate::{
batch_verifier::BulletproofsPlusBatchVerifier,
plus::{
ScalarVector, PointVector, GeneratorsList, BpPlusGenerators,
weighted_inner_product::{WipStatement, WipWitness},
},
};
#[test]
fn test_zero_weighted_inner_product() {
#[allow(non_snake_case)]
let P = EdwardsPoint::identity();
let y = Scalar::random(&mut OsRng);
let generators = BpPlusGenerators::new().reduce(1);
let statement = WipStatement::new(generators, P, y);
let witness = WipWitness::new(ScalarVector::new(1), ScalarVector::new(1), Scalar::ZERO).unwrap();
let transcript = Scalar::random(&mut OsRng);
let proof = statement.clone().prove(&mut OsRng, transcript, &witness).unwrap();
let mut verifier = BulletproofsPlusBatchVerifier::default();
statement.verify(&mut OsRng, &mut verifier, transcript, proof);
assert!(verifier.verify());
}
#[test]
fn test_weighted_inner_product() {
// P = sum(g_bold * a, h_bold * b, g * (a * y * b), h * alpha)
let mut verifier = BulletproofsPlusBatchVerifier::default();
let generators = BpPlusGenerators::new();
for i in [1, 2, 4, 8, 16, 32] {
let generators = generators.reduce(i);
let g = BpPlusGenerators::g();
let h = BpPlusGenerators::h();
assert_eq!(generators.len(), i);
let mut g_bold = vec![];
let mut h_bold = vec![];
for i in 0 .. i {
g_bold.push(generators.generator(GeneratorsList::GBold, i));
h_bold.push(generators.generator(GeneratorsList::HBold, i));
}
let g_bold = PointVector(g_bold);
let h_bold = PointVector(h_bold);
let mut a = ScalarVector::new(i);
let mut b = ScalarVector::new(i);
let alpha = Scalar::random(&mut OsRng);
let y = Scalar::random(&mut OsRng);
let mut y_vec = ScalarVector::new(g_bold.len());
y_vec[0] = y;
for i in 1 .. y_vec.len() {
y_vec[i] = y_vec[i - 1] * y;
}
for i in 0 .. i {
a[i] = Scalar::random(&mut OsRng);
b[i] = Scalar::random(&mut OsRng);
}
#[allow(non_snake_case)]
let P = g_bold.multiexp(&a) +
h_bold.multiexp(&b) +
(g * a.clone().weighted_inner_product(&b, &y_vec)) +
(h * alpha);
let statement = WipStatement::new(generators, P, y);
let witness = WipWitness::new(a, b, alpha).unwrap();
let transcript = Scalar::random(&mut OsRng);
let proof = statement.clone().prove(&mut OsRng, transcript, &witness).unwrap();
statement.verify(&mut OsRng, &mut verifier, transcript, proof);
}
assert!(verifier.verify());
}

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@@ -52,8 +52,6 @@ std = [
"zeroize/std",
"subtle/std",
"curve25519-dalek/precomputed-tables",
"rand_chacha?/std",
"transcript?/std",
"group?/alloc",