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zk-token-sdk: generalize range proof (#23506) 

* zk-token-sdk: update range proof in transfers for more flexible setting of params

* zk-token-sdk: clippy
This commit is contained in:
samkim-crypto 2022-03-07 12:27:56 -05:00 committed by GitHub
parent 3a0271c113
commit 08c9a650db
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 250 additions and 116 deletions
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2
zk-token-sdk/src/errors.rs
View File

@ -24,6 +24,8 @@ pub enum ProofError {
"`zk_token_elgamal::pod::ElGamalCiphertext` contains invalid ElGamalCiphertext ciphertext"
)]
InconsistentCTData,
#[error("failed to decrypt ciphertext from transfer data")]
Decryption,
}
#[derive(Error, Clone, Debug, Eq, PartialEq)]

34
zk-token-sdk/src/instruction/mod.rs
View File

@ -21,10 +21,6 @@ pub use {
withdraw_withheld::WithdrawWithheldTokensData,
};
/// Constant for 2^32
#[cfg(not(target_arch = "bpf"))]
const TWO_32: u64 = 4294967296;
#[cfg(not(target_arch = "bpf"))]
pub trait Verifiable {
fn verify(&self) -> Result<(), ProofError>;
@ -38,35 +34,45 @@ pub enum Role {
Auditor,
}
/// Split u64 number into two u32 numbers
/// Takes in a 64-bit number `amount` and a bit length `bit_length`. It returns:
/// - the `bit_length` low bits of `amount` interpretted as u64
/// - the (64 - `bit_length`) high bits of `amount` interpretted as u64
#[cfg(not(target_arch = "bpf"))]
pub fn split_u64_into_u32(amount: u64) -> (u32, u32) {
let lo = amount as u32;
let hi = (amount >> 32) as u32;
pub fn split_u64(amount: u64, bit_length: usize) -> (u64, u64) {
assert!(bit_length <= 64);
let lo = amount << (64 - bit_length) >> (64 - bit_length);
let hi = amount >> bit_length;
(lo, hi)
}
#[cfg(not(target_arch = "bpf"))]
fn combine_u32_ciphertexts(
fn combine_lo_hi_ciphertexts(
ciphertext_lo: &ElGamalCiphertext,
ciphertext_hi: &ElGamalCiphertext,
bit_length: usize,
) -> ElGamalCiphertext {
ciphertext_lo + &(ciphertext_hi * &Scalar::from(TWO_32))
let two_power = (1_u64) << bit_length;
ciphertext_lo + &(ciphertext_hi * &Scalar::from(two_power))
}
#[cfg(not(target_arch = "bpf"))]
pub fn combine_u32_commitments(
pub fn combine_lo_hi_commitments(
comm_lo: &PedersenCommitment,
comm_hi: &PedersenCommitment,
bit_length: usize,
) -> PedersenCommitment {
comm_lo + comm_hi * &Scalar::from(TWO_32)
let two_power = (1_u64) << bit_length;
comm_lo + comm_hi * &Scalar::from(two_power)
}
#[cfg(not(target_arch = "bpf"))]
pub fn combine_u32_openings(
pub fn combine_lo_hi_openings(
opening_lo: &PedersenOpening,
opening_hi: &PedersenOpening,
bit_length: usize,
) -> PedersenOpening {
opening_lo + opening_hi * &Scalar::from(TWO_32)
let two_power = (1_u64) << bit_length;
opening_lo + opening_hi * &Scalar::from(two_power)
}

154
zk-token-sdk/src/instruction/transfer.rs
View File

@ -12,7 +12,7 @@ use {
pedersen::{Pedersen, PedersenCommitment, PedersenOpening},
},
errors::ProofError,
instruction::{combine_u32_ciphertexts, split_u64_into_u32, Role, Verifiable, TWO_32},
instruction::{combine_lo_hi_ciphertexts, split_u64, Role, Verifiable},
range_proof::RangeProof,
sigma_proofs::{
equality_proof::CtxtCommEqualityProof, validity_proof::AggregatedValidityProof,
@ -27,10 +27,18 @@ use {
#[cfg(not(target_arch = "bpf"))]
const TRANSFER_SOURCE_AMOUNT_BIT_LENGTH: usize = 64;
#[cfg(not(target_arch = "bpf"))]
const TRANSFER_AMOUNT_LO_BIT_LENGTH: usize = 32;
const TRANSFER_AMOUNT_LO_BIT_LENGTH: usize = 16;
#[cfg(not(target_arch = "bpf"))]
const TRANSFER_AMOUNT_LO_NEGATED_BIT_LENGTH: usize = 16;
#[cfg(not(target_arch = "bpf"))]
const TRANSFER_AMOUNT_HI_BIT_LENGTH: usize = 32;
#[cfg(not(target_arch = "bpf"))]
lazy_static::lazy_static! {
pub static ref COMMITMENT_MAX: PedersenCommitment = Pedersen::encode(1_u64 <<
TRANSFER_AMOUNT_LO_NEGATED_BIT_LENGTH);
}
#[derive(Clone)]
#[repr(C)]
#[cfg(not(target_arch = "bpf"))]
@ -44,7 +52,7 @@ pub struct TransferAmountEncryption {
#[cfg(not(target_arch = "bpf"))]
impl TransferAmountEncryption {
pub fn new(
amount: u32,
amount: u64,
source_pubkey: &ElGamalPubkey,
destination_pubkey: &ElGamalPubkey,
auditor_pubkey: &ElGamalPubkey,
@ -99,7 +107,7 @@ impl TransferData {
(destination_pubkey, auditor_pubkey): (&ElGamalPubkey, &ElGamalPubkey),
) -> Result<Self, ProofError> {
// split and encrypt transfer amount
let (amount_lo, amount_hi) = split_u64_into_u32(transfer_amount);
let (amount_lo, amount_hi) = split_u64(transfer_amount, TRANSFER_AMOUNT_LO_BIT_LENGTH);
let (ciphertext_lo, opening_lo) = TransferAmountEncryption::new(
amount_lo,
@ -107,6 +115,7 @@ impl TransferData {
destination_pubkey,
auditor_pubkey,
);
let (ciphertext_hi, opening_hi) = TransferAmountEncryption::new(
amount_hi,
&source_keypair.public,
@ -130,7 +139,11 @@ impl TransferData {
};
let new_source_ciphertext = ciphertext_old_source
- combine_u32_ciphertexts(&transfer_amount_lo_source, &transfer_amount_hi_source);
- combine_lo_hi_ciphertexts(
&transfer_amount_lo_source,
&transfer_amount_hi_source,
TRANSFER_AMOUNT_LO_BIT_LENGTH,
);
// generate transcript and append all public inputs
let pod_transfer_pubkeys = pod::TransferPubkeys {
@ -201,11 +214,6 @@ impl TransferData {
}
/// Decrypts transfer amount from transfer data
///
/// TODO: This function should run in constant time. Use `subtle::Choice` for the if statement
/// and make sure that the function does not terminate prematurely due to errors
///
/// TODO: Define specific error type for decryption error
pub fn decrypt_amount(&self, role: Role, sk: &ElGamalSecretKey) -> Result<u64, ProofError> {
let ciphertext_lo = self.ciphertext_lo(role)?;
let ciphertext_hi = self.ciphertext_hi(role)?;
@ -214,9 +222,10 @@ impl TransferData {
let amount_hi = ciphertext_hi.decrypt_u32(sk);
if let (Some(amount_lo), Some(amount_hi)) = (amount_lo, amount_hi) {
Ok(amount_lo + TWO_32 * amount_hi)
let two_power = 1 << TRANSFER_AMOUNT_LO_BIT_LENGTH;
Ok(amount_lo + two_power * amount_hi)
} else {
Err(ProofError::Verification)
Err(ProofError::Decryption)
}
}
}
@ -252,7 +261,7 @@ impl Verifiable for TransferData {
#[repr(C)]
pub struct TransferProof {
/// New Pedersen commitment for the remaining balance in source
pub commitment_new_source: pod::PedersenCommitment,
pub new_source_commitment: pod::PedersenCommitment,
/// Associated equality proof
pub equality_proof: pod::CtxtCommEqualityProof,
@ -295,7 +304,7 @@ impl TransferProof {
}
pub fn new(
(transfer_amount_lo, transfer_amount_hi): (u32, u32),
(transfer_amount_lo, transfer_amount_hi): (u64, u64),
source_keypair: &ElGamalKeypair,
(destination_pubkey, auditor_pubkey): (&ElGamalPubkey, &ElGamalPubkey),
opening_lo: &PedersenOpening,
@ -304,10 +313,10 @@ impl TransferProof {
transcript: &mut Transcript,
) -> Self {
// generate a Pedersen commitment for the remaining balance in source
let (commitment_new_source, source_opening) = Pedersen::new(source_new_balance);
let (new_source_commitment, source_opening) = Pedersen::new(source_new_balance);
let pod_commitment_new_source: pod::PedersenCommitment = commitment_new_source.into();
transcript.append_commitment(b"commitment-new-source", &pod_commitment_new_source);
let pod_new_source_commitment: pod::PedersenCommitment = new_source_commitment.into();
transcript.append_commitment(b"commitment-new-source", &pod_new_source_commitment);
// generate equality_proof
let equality_proof = CtxtCommEqualityProof::new(
@ -327,23 +336,46 @@ impl TransferProof {
);
// generate the range proof
let range_proof = RangeProof::new(
vec![
source_new_balance,
transfer_amount_lo as u64,
transfer_amount_hi as u64,
],
vec![
TRANSFER_SOURCE_AMOUNT_BIT_LENGTH,
TRANSFER_AMOUNT_LO_BIT_LENGTH,
TRANSFER_AMOUNT_HI_BIT_LENGTH,
],
vec![&source_opening, opening_lo, opening_hi],
transcript,
);
let range_proof = if TRANSFER_AMOUNT_LO_BIT_LENGTH == 32 {
RangeProof::new(
vec![
source_new_balance,
transfer_amount_lo as u64,
transfer_amount_hi as u64,
],
vec![
TRANSFER_SOURCE_AMOUNT_BIT_LENGTH,
TRANSFER_AMOUNT_LO_BIT_LENGTH,
TRANSFER_AMOUNT_HI_BIT_LENGTH,
],
vec![&source_opening, opening_lo, opening_hi],
transcript,
)
} else {
let transfer_amount_lo_negated =
(1 << TRANSFER_AMOUNT_LO_NEGATED_BIT_LENGTH) - transfer_amount_lo as u64;
let opening_lo_negated = &PedersenOpening::default() - opening_lo;
RangeProof::new(
vec![
source_new_balance,
transfer_amount_lo as u64,
transfer_amount_lo_negated,
transfer_amount_hi as u64,
],
vec![
TRANSFER_SOURCE_AMOUNT_BIT_LENGTH,
TRANSFER_AMOUNT_LO_BIT_LENGTH,
TRANSFER_AMOUNT_LO_NEGATED_BIT_LENGTH,
TRANSFER_AMOUNT_HI_BIT_LENGTH,
],
vec![&source_opening, opening_lo, &opening_lo_negated, opening_hi],
transcript,
)
};
Self {
commitment_new_source: pod_commitment_new_source,
new_source_commitment: pod_new_source_commitment,
equality_proof: equality_proof.into(),
validity_proof: validity_proof.into(),
range_proof: range_proof.try_into().expect("range proof: length error"),
@ -358,9 +390,9 @@ impl TransferProof {
ciphertext_new_spendable: &ElGamalCiphertext,
transcript: &mut Transcript,
) -> Result<(), ProofError> {
transcript.append_commitment(b"commitment-new-source", &self.commitment_new_source);
transcript.append_commitment(b"commitment-new-source", &self.new_source_commitment);
let commitment: PedersenCommitment = self.commitment_new_source.try_into()?;
let commitment: PedersenCommitment = self.new_source_commitment.try_into()?;
let equality_proof: CtxtCommEqualityProof = self.equality_proof.try_into()?;
let aggregated_validity_proof: AggregatedValidityProof = self.validity_proof.try_into()?;
let range_proof: RangeProof = self.range_proof.try_into()?;
@ -391,16 +423,40 @@ impl TransferProof {
)?;
// verify range proof
let commitment_new_source = self.commitment_new_source.try_into()?;
range_proof.verify(
vec![
&commitment_new_source,
&ciphertext_lo.commitment,
&ciphertext_hi.commitment,
],
vec![64_usize, 32_usize, 32_usize],
transcript,
)?;
let new_source_commitment = self.new_source_commitment.try_into()?;
if TRANSFER_AMOUNT_LO_BIT_LENGTH == 32 {
range_proof.verify(
vec![
&new_source_commitment,
&ciphertext_lo.commitment,
&ciphertext_hi.commitment,
],
vec![
TRANSFER_SOURCE_AMOUNT_BIT_LENGTH,
TRANSFER_AMOUNT_LO_BIT_LENGTH,
TRANSFER_AMOUNT_HI_BIT_LENGTH,
],
transcript,
)?;
} else {
let commitment_lo_negated = &(*COMMITMENT_MAX) - &ciphertext_lo.commitment;
range_proof.verify(
vec![
&new_source_commitment,
&ciphertext_lo.commitment,
&commitment_lo_negated,
&ciphertext_hi.commitment,
],
vec![
TRANSFER_SOURCE_AMOUNT_BIT_LENGTH,
TRANSFER_AMOUNT_LO_BIT_LENGTH,
TRANSFER_AMOUNT_LO_NEGATED_BIT_LENGTH,
TRANSFER_AMOUNT_HI_BIT_LENGTH,
],
transcript,
)?;
}
Ok(())
}
@ -492,11 +548,11 @@ mod test {
} = ElGamalKeypair::new_rand();
// create source account spendable ciphertext
let spendable_balance: u64 = 77;
let spendable_balance: u64 = 770000;
let spendable_ciphertext = source_keypair.public.encrypt(spendable_balance);
// transfer amount
let transfer_amount: u64 = 55;
let transfer_amount: u64 = 550000;
// create transfer data
let transfer_data = TransferData::new(
@ -511,19 +567,19 @@ mod test {
transfer_data
.decrypt_amount(Role::Source, &source_keypair.secret)
.unwrap(),
55_u64,
550000_u64,
);
assert_eq!(
transfer_data.decrypt_amount(Role::Dest, &dest_sk).unwrap(),
55_u64,
550000_u64,
);
assert_eq!(
transfer_data
.decrypt_amount(Role::Auditor, &auditor_sk)
.unwrap(),
55_u64,
550000_u64,
);
}
}

176
zk-token-sdk/src/instruction/transfer_with_fee.rs
View File

@ -13,8 +13,8 @@ use {
},
errors::ProofError,
instruction::{
combine_u32_ciphertexts, combine_u32_commitments, combine_u32_openings,
split_u64_into_u32, transfer::TransferAmountEncryption, Role, Verifiable, TWO_32,
combine_lo_hi_ciphertexts, combine_lo_hi_commitments, combine_lo_hi_openings,
split_u64, transfer::TransferAmountEncryption, Role, Verifiable,
},
range_proof::RangeProof,
sigma_proofs::{
@ -39,7 +39,9 @@ const ONE_IN_BASIS_POINTS: u128 = MAX_FEE_BASIS_POINTS as u128;
#[cfg(not(target_arch = "bpf"))]
const TRANSFER_WITH_FEE_SOURCE_AMOUNT_BIT_LENGTH: usize = 64;
#[cfg(not(target_arch = "bpf"))]
const TRANSFER_WITH_FEE_AMOUNT_LO_BIT_LENGTH: usize = 32;
const TRANSFER_WITH_FEE_AMOUNT_LO_BIT_LENGTH: usize = 16;
#[cfg(not(target_arch = "bpf"))]
const TRANSFER_WITH_FEE_AMOUNT_LO_NEGATED_BIT_LENGTH: usize = 16;
#[cfg(not(target_arch = "bpf"))]
const TRANSFER_WITH_FEE_AMOUNT_HI_BIT_LENGTH: usize = 32;
#[cfg(not(target_arch = "bpf"))]
@ -47,6 +49,8 @@ const TRANSFER_WITH_FEE_DELTA_BIT_LENGTH: usize = 64;
#[cfg(not(target_arch = "bpf"))]
lazy_static::lazy_static! {
pub static ref COMMITMENT_MAX: PedersenCommitment = Pedersen::encode(1_u64 <<
TRANSFER_WITH_FEE_AMOUNT_LO_NEGATED_BIT_LENGTH);
pub static ref COMMITMENT_MAX_FEE_BASIS_POINTS: PedersenCommitment = Pedersen::encode(MAX_FEE_BASIS_POINTS);
}
@ -87,7 +91,8 @@ impl TransferWithFeeData {
withdraw_withheld_authority_pubkey: &ElGamalPubkey,
) -> Result<Self, ProofError> {
// split and encrypt transfer amount
let (amount_lo, amount_hi) = split_u64_into_u32(transfer_amount);
let (amount_lo, amount_hi) =
split_u64(transfer_amount, TRANSFER_WITH_FEE_AMOUNT_LO_BIT_LENGTH);
let (ciphertext_lo, opening_lo) = TransferAmountEncryption::new(
amount_lo,
@ -118,7 +123,11 @@ impl TransferWithFeeData {
};
let new_source_ciphertext = old_source_ciphertext
- combine_u32_ciphertexts(&transfer_amount_lo_source, &transfer_amount_hi_source);
- combine_lo_hi_ciphertexts(
&transfer_amount_lo_source,
&transfer_amount_hi_source,
TRANSFER_WITH_FEE_AMOUNT_LO_BIT_LENGTH,
);
// calculate and encrypt fee
let (fee_amount, delta_fee) =
@ -212,11 +221,6 @@ impl TransferWithFeeData {
}
/// Decrypts transfer amount from transfer-with-fee data
///
/// TODO: This function should run in constant time. Use `subtle::Choice` for the if statement
/// and make sure that the function does not terminate prematurely due to errors
///
/// TODO: Define specific error type for decryption error
pub fn decrypt_amount(&self, role: Role, sk: &ElGamalSecretKey) -> Result<u64, ProofError> {
let ciphertext_lo = self.ciphertext_lo(role)?;
let ciphertext_hi = self.ciphertext_hi(role)?;
@ -225,7 +229,8 @@ impl TransferWithFeeData {
let amount_hi = ciphertext_hi.decrypt_u32(sk);
if let (Some(amount_lo), Some(amount_hi)) = (amount_lo, amount_hi) {
Ok(amount_lo + TWO_32 * amount_hi)
let two_power = 1 << TRANSFER_WITH_FEE_AMOUNT_LO_BIT_LENGTH;
Ok(amount_lo + two_power * amount_hi)
} else {
Err(ProofError::Verification)
}
@ -324,8 +329,8 @@ impl TransferWithFeeProof {
#[allow(clippy::too_many_arguments)]
#[allow(clippy::many_single_char_names)]
pub fn new(
transfer_amount_lo_data: (u32, &TransferAmountEncryption, &PedersenOpening),
transfer_amount_hi_data: (u32, &TransferAmountEncryption, &PedersenOpening),
transfer_amount_lo_data: (u64, &TransferAmountEncryption, &PedersenOpening),
transfer_amount_hi_data: (u64, &TransferAmountEncryption, &PedersenOpening),
source_keypair: &ElGamalKeypair,
(destination_pubkey, auditor_pubkey): (&ElGamalPubkey, &ElGamalPubkey),
(source_new_balance, new_source_ciphertext): (u64, &ElGamalCiphertext),
@ -388,31 +393,66 @@ impl TransferWithFeeProof {
transcript,
);
// generate the range proof
let opening_claimed_negated = &PedersenOpening::default() - &opening_claimed;
let range_proof = RangeProof::new(
vec![
source_new_balance,
transfer_amount_lo as u64,
transfer_amount_hi as u64,
delta_fee,
MAX_FEE_BASIS_POINTS - delta_fee,
],
vec![
TRANSFER_WITH_FEE_SOURCE_AMOUNT_BIT_LENGTH,
TRANSFER_WITH_FEE_AMOUNT_LO_BIT_LENGTH,
TRANSFER_WITH_FEE_AMOUNT_HI_BIT_LENGTH,
TRANSFER_WITH_FEE_DELTA_BIT_LENGTH,
TRANSFER_WITH_FEE_DELTA_BIT_LENGTH,
],
vec![
&opening_source,
opening_lo,
opening_hi,
&opening_claimed,
&opening_claimed_negated,
],
transcript,
);
let range_proof = if TRANSFER_WITH_FEE_AMOUNT_LO_BIT_LENGTH == 32 {
RangeProof::new(
vec![
source_new_balance,
transfer_amount_lo as u64,
transfer_amount_hi as u64,
delta_fee,
MAX_FEE_BASIS_POINTS - delta_fee,
],
vec![
TRANSFER_WITH_FEE_SOURCE_AMOUNT_BIT_LENGTH,
TRANSFER_WITH_FEE_AMOUNT_LO_BIT_LENGTH,
TRANSFER_WITH_FEE_AMOUNT_HI_BIT_LENGTH,
TRANSFER_WITH_FEE_DELTA_BIT_LENGTH,
TRANSFER_WITH_FEE_DELTA_BIT_LENGTH,
],
vec![
&opening_source,
opening_lo,
opening_hi,
&opening_claimed,
&opening_claimed_negated,
],
transcript,
)
} else {
let transfer_amount_lo_negated =
(1 << TRANSFER_WITH_FEE_AMOUNT_LO_NEGATED_BIT_LENGTH) - transfer_amount_lo as u64;
let opening_lo_negated = &PedersenOpening::default() - opening_lo;
RangeProof::new(
vec![
source_new_balance,
transfer_amount_lo as u64,
transfer_amount_lo_negated,
transfer_amount_hi as u64,
delta_fee,
MAX_FEE_BASIS_POINTS - delta_fee,
],
vec![
TRANSFER_WITH_FEE_SOURCE_AMOUNT_BIT_LENGTH,
TRANSFER_WITH_FEE_AMOUNT_LO_BIT_LENGTH,
TRANSFER_WITH_FEE_AMOUNT_LO_NEGATED_BIT_LENGTH,
TRANSFER_WITH_FEE_AMOUNT_HI_BIT_LENGTH,
TRANSFER_WITH_FEE_DELTA_BIT_LENGTH,
TRANSFER_WITH_FEE_DELTA_BIT_LENGTH,
],
vec![
&opening_source,
opening_lo,
&opening_lo_negated,
opening_hi,
&opening_claimed,
&opening_claimed_negated,
],
transcript,
)
};
Self {
new_source_commitment: pod_new_source_commitment,
@ -458,8 +498,6 @@ impl TransferWithFeeProof {
transcript,
)?;
println!("here");
// verify that the transfer amount is encrypted correctly
ciphertext_amount_validity_proof.verify(
(
@ -504,18 +542,38 @@ impl TransferWithFeeProof {
transcript,
)?;
// verify range proof
let new_source_commitment = self.new_source_commitment.try_into()?;
let claimed_commitment_negated = &(*COMMITMENT_MAX_FEE_BASIS_POINTS) - &claimed_commitment;
range_proof.verify(
vec![
&new_source_commitment,
&ciphertext_lo.commitment,
&ciphertext_hi.commitment,
&claimed_commitment,
&claimed_commitment_negated,
],
vec![64, 32, 32, 64, 64],
transcript,
)?;
if TRANSFER_WITH_FEE_AMOUNT_LO_BIT_LENGTH == 32 {
range_proof.verify(
vec![
&new_source_commitment,
&ciphertext_lo.commitment,
&ciphertext_hi.commitment,
&claimed_commitment,
&claimed_commitment_negated,
],
vec![64, 32, 32, 64, 64],
transcript,
)?;
} else {
let commitment_lo_negated = &(*COMMITMENT_MAX) - &ciphertext_lo.commitment;
range_proof.verify(
vec![
&new_source_commitment,
&ciphertext_lo.commitment,
&commitment_lo_negated,
&ciphertext_hi.commitment,
&claimed_commitment,
&claimed_commitment_negated,
],
vec![64, 16, 16, 32, 64, 64],
transcript,
)?;
}
Ok(())
}
@ -656,10 +714,18 @@ fn compute_delta_commitment_and_opening(
let fee_rate_scalar = Scalar::from(fee_rate_basis_points);
let delta_commitment = fee_commitment * Scalar::from(MAX_FEE_BASIS_POINTS)
- &(&combine_u32_commitments(commitment_lo, commitment_hi) * &fee_rate_scalar);
- &(&combine_lo_hi_commitments(
commitment_lo,
commitment_hi,
TRANSFER_WITH_FEE_AMOUNT_LO_BIT_LENGTH,
) * &fee_rate_scalar);
let opening_delta = opening_fee * Scalar::from(MAX_FEE_BASIS_POINTS)
- &(&combine_u32_openings(opening_lo, opening_hi) * &fee_rate_scalar);
- &(&combine_lo_hi_openings(
opening_lo,
opening_hi,
TRANSFER_WITH_FEE_AMOUNT_LO_BIT_LENGTH,
) * &fee_rate_scalar);
(delta_commitment, opening_delta)
}
@ -674,7 +740,11 @@ fn compute_delta_commitment(
let fee_rate_scalar = Scalar::from(fee_rate_basis_points);
fee_commitment * Scalar::from(MAX_FEE_BASIS_POINTS)
- &(&combine_u32_commitments(commitment_lo, commitment_hi) * &fee_rate_scalar)
- &(&combine_lo_hi_commitments(
commitment_lo,
commitment_hi,
TRANSFER_WITH_FEE_AMOUNT_LO_BIT_LENGTH,
) * &fee_rate_scalar)
}
#[cfg(test)]