Use `bls.Scalar` as the base class for `BLSFieldElement` (#3907)

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Justin Traglia 2024-09-27 07:19:04 -05:00 committed by GitHub
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13 changed files with 248 additions and 215 deletions

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@ -34,7 +34,7 @@ MARKDOWN_FILES = $(wildcard $(SPEC_DIR)/*/*.md) \
$(wildcard $(SPEC_DIR)/_features/*/*/*.md) \
$(wildcard $(SSZ_DIR)/*.md)
ALL_EXECUTABLE_SPEC_NAMES = phase0 altair bellatrix capella deneb electra whisk eip6800 eip7732
ALL_EXECUTABLE_SPEC_NAMES = phase0 altair bellatrix capella deneb electra whisk eip6800 eip7594 eip7732
# The parameters for commands. Use `foreach` to avoid listing specs again.
COVERAGE_SCOPE := $(foreach S,$(ALL_EXECUTABLE_SPEC_NAMES), --cov=eth2spec.$S.$(TEST_PRESET_TYPE))
PYLINT_SCOPE := $(foreach S,$(ALL_EXECUTABLE_SPEC_NAMES), ./eth2spec/$S)

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@ -119,6 +119,7 @@ def objects_to_spec(preset_name: str,
hardcoded_func_dep_presets = reduce(lambda obj, builder: {**obj, **builder.hardcoded_func_dep_presets(spec_object)}, builders, {})
# Concatenate all strings
imports = reduce(lambda txt, builder: (txt + "\n\n" + builder.imports(preset_name) ).strip("\n"), builders, "")
classes = reduce(lambda txt, builder: (txt + "\n\n" + builder.classes() ).strip("\n"), builders, "")
preparations = reduce(lambda txt, builder: (txt + "\n\n" + builder.preparations() ).strip("\n"), builders, "")
sundry_functions = reduce(lambda txt, builder: (txt + "\n\n" + builder.sundry_functions() ).strip("\n"), builders, "")
# Keep engine from the most recent fork
@ -154,6 +155,8 @@ def objects_to_spec(preset_name: str,
constant_vars_spec,
preset_vars_spec,
config_spec,
# Custom classes which are not required to be SSZ containers.
classes,
ordered_class_objects_spec,
protocols_spec,
functions_spec,

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@ -15,6 +15,13 @@ class BaseSpecBuilder(ABC):
"""
return ""
@classmethod
def classes(cls) -> str:
"""
Define special classes.
"""
return ""
@classmethod
def preparations(cls) -> str:
"""

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@ -12,6 +12,21 @@ class DenebSpecBuilder(BaseSpecBuilder):
from eth2spec.capella import {preset_name} as capella
'''
@classmethod
def classes(cls):
return f'''
class BLSFieldElement(bls.Scalar):
pass
class Polynomial(list):
def __init__(self, evals: Optional[Sequence[BLSFieldElement]] = None):
if evals is None:
evals = [BLSFieldElement(0)] * FIELD_ELEMENTS_PER_BLOB
if len(evals) != FIELD_ELEMENTS_PER_BLOB:
raise ValueError("expected FIELD_ELEMENTS_PER_BLOB evals")
super().__init__(evals)
'''
@classmethod
def preparations(cls):

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@ -12,12 +12,41 @@ class EIP7594SpecBuilder(BaseSpecBuilder):
return f'''
from eth2spec.deneb import {preset_name} as deneb
'''
@classmethod
def classes(cls):
return f'''
class PolynomialCoeff(list):
def __init__(self, coeffs: Sequence[BLSFieldElement]):
if len(coeffs) > FIELD_ELEMENTS_PER_EXT_BLOB:
raise ValueError("expected <= FIELD_ELEMENTS_PER_EXT_BLOB coeffs")
super().__init__(coeffs)
class Coset(list):
def __init__(self, coeffs: Optional[Sequence[BLSFieldElement]] = None):
if coeffs is None:
coeffs = [BLSFieldElement(0)] * FIELD_ELEMENTS_PER_CELL
if len(coeffs) != FIELD_ELEMENTS_PER_CELL:
raise ValueError("expected FIELD_ELEMENTS_PER_CELL coeffs")
super().__init__(coeffs)
class CosetEvals(list):
def __init__(self, evals: Optional[Sequence[BLSFieldElement]] = None):
if evals is None:
evals = [BLSFieldElement(0)] * FIELD_ELEMENTS_PER_CELL
if len(evals) != FIELD_ELEMENTS_PER_CELL:
raise ValueError("expected FIELD_ELEMENTS_PER_CELL coeffs")
super().__init__(evals)
'''
@classmethod
def sundry_functions(cls) -> str:
return """
def retrieve_column_sidecars(beacon_block_root: Root) -> Sequence[DataColumnSidecar]:
# pylint: disable=unused-argument
return []
"""

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@ -183,7 +183,7 @@ def _update_constant_vars_with_kzg_setups(constant_vars, preset_name):
constant_vars['KZG_SETUP_G1_MONOMIAL'] = VariableDefinition(constant_vars['KZG_SETUP_G1_MONOMIAL'].value, str(kzg_setups[0]), comment, None)
constant_vars['KZG_SETUP_G1_LAGRANGE'] = VariableDefinition(constant_vars['KZG_SETUP_G1_LAGRANGE'].value, str(kzg_setups[1]), comment, None)
constant_vars['KZG_SETUP_G2_MONOMIAL'] = VariableDefinition(constant_vars['KZG_SETUP_G2_MONOMIAL'].value, str(kzg_setups[2]), comment, None)
def get_spec(file_name: Path, preset: Dict[str, str], config: Dict[str, str], preset_name=str) -> SpecObject:
functions: Dict[str, str] = {}
@ -261,10 +261,17 @@ def get_spec(file_name: Path, preset: Dict[str, str], config: Dict[str, str], pr
# marko parses `**X**` as a list containing a X
description = description[0].children
if isinstance(name, list):
# marko parses `[X]()` as a list containing a X
name = name[0].children
if isinstance(value, list):
# marko parses `**X**` as a list containing a X
value = value[0].children
# Skip types that have been defined elsewhere
if description is not None and description.startswith("<!-- predefined-type -->"):
continue
if not _is_constant_id(name):
# Check for short type declarations
if value.startswith(("uint", "Bytes", "ByteList", "Union", "Vector", "List", "ByteVector")):
@ -569,7 +576,7 @@ setup(
RUAMEL_YAML_VERSION,
"lru-dict==1.2.0",
MARKO_VERSION,
"py_arkworks_bls12381==0.3.4",
"curdleproofs==0.1.1",
"py_arkworks_bls12381==0.3.8",
"curdleproofs==0.1.2",
]
)

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@ -9,6 +9,7 @@
- [Introduction](#introduction)
- [Public Methods](#public-methods)
- [Custom types](#custom-types)
- [Cryptographic types](#cryptographic-types)
- [Preset](#preset)
- [Cells](#cells)
- [Helper functions](#helper-functions)
@ -69,13 +70,18 @@ The following is a list of the public methods:
| Name | SSZ equivalent | Description |
| - | - | - |
| `PolynomialCoeff` | `List[BLSFieldElement, FIELD_ELEMENTS_PER_EXT_BLOB]` | A polynomial in coefficient form |
| `Coset` | `Vector[BLSFieldElement, FIELD_ELEMENTS_PER_CELL]` | The evaluation domain of a cell |
| `CosetEvals` | `Vector[BLSFieldElement, FIELD_ELEMENTS_PER_CELL]` | The internal representation of a cell (the evaluations over its Coset) |
| `Cell` | `ByteVector[BYTES_PER_FIELD_ELEMENT * FIELD_ELEMENTS_PER_CELL]` | The unit of blob data that can come with its own KZG proof |
| `CellIndex` | `uint64` | Validation: `x < CELLS_PER_EXT_BLOB` |
| `CommitmentIndex` | `uint64` | The type which represents the index of an element in the list of commitments |
## Cryptographic types
| Name | SSZ equivalent | Description |
| - | - | - |
| [`PolynomialCoeff`](https://github.com/ethereum/consensus-specs/blob/36a5719b78523c057065515c8f8fcaeba75d065b/pysetup/spec_builders/eip7594.py#L20-L24) | `List[BLSFieldElement, FIELD_ELEMENTS_PER_EXT_BLOB]` | <!-- predefined-type --> A polynomial in coefficient form |
| [`Coset`](https://github.com/ethereum/consensus-specs/blob/36a5719b78523c057065515c8f8fcaeba75d065b/pysetup/spec_builders/eip7594.py#L27-L33) | `Vector[BLSFieldElement, FIELD_ELEMENTS_PER_CELL]` | <!-- predefined-type --> The evaluation domain of a cell |
| [`CosetEvals`](https://github.com/ethereum/consensus-specs/blob/36a5719b78523c057065515c8f8fcaeba75d065b/pysetup/spec_builders/eip7594.py#L36-L42) | `Vector[BLSFieldElement, FIELD_ELEMENTS_PER_CELL]` | <!-- predefined-type --> A cell's evaluations over its coset |
## Preset
### Cells
@ -101,13 +107,12 @@ def cell_to_coset_evals(cell: Cell) -> CosetEvals:
"""
Convert an untrusted ``Cell`` into a trusted ``CosetEvals``.
"""
evals = []
evals = CosetEvals()
for i in range(FIELD_ELEMENTS_PER_CELL):
start = i * BYTES_PER_FIELD_ELEMENT
end = (i + 1) * BYTES_PER_FIELD_ELEMENT
value = bytes_to_bls_field(cell[start:end])
evals.append(value)
return CosetEvals(evals)
evals[i] = bytes_to_bls_field(cell[start:end])
return evals
```
#### `coset_evals_to_cell`
@ -128,17 +133,16 @@ def coset_evals_to_cell(coset_evals: CosetEvals) -> Cell:
#### `_fft_field`
```python
def _fft_field(vals: Sequence[BLSFieldElement],
roots_of_unity: Sequence[BLSFieldElement]) -> Sequence[BLSFieldElement]:
def _fft_field(vals: Sequence[BLSFieldElement], roots_of_unity: Sequence[BLSFieldElement]) -> Sequence[BLSFieldElement]:
if len(vals) == 1:
return vals
L = _fft_field(vals[::2], roots_of_unity[::2])
R = _fft_field(vals[1::2], roots_of_unity[::2])
o = [BLSFieldElement(0) for _ in vals]
for i, (x, y) in enumerate(zip(L, R)):
y_times_root = (int(y) * int(roots_of_unity[i])) % BLS_MODULUS
o[i] = BLSFieldElement((int(x) + y_times_root) % BLS_MODULUS)
o[i + len(L)] = BLSFieldElement((int(x) - y_times_root + BLS_MODULUS) % BLS_MODULUS)
y_times_root = y * roots_of_unity[i]
o[i] = x + y_times_root
o[i + len(L)] = x - y_times_root
return o
```
@ -150,9 +154,8 @@ def fft_field(vals: Sequence[BLSFieldElement],
inv: bool=False) -> Sequence[BLSFieldElement]:
if inv:
# Inverse FFT
invlen = pow(len(vals), BLS_MODULUS - 2, BLS_MODULUS)
return [BLSFieldElement((int(x) * invlen) % BLS_MODULUS)
for x in _fft_field(vals, list(roots_of_unity[0:1]) + list(roots_of_unity[:0:-1]))]
invlen = BLSFieldElement(len(vals)).pow(BLSFieldElement(BLS_MODULUS - 2))
return [x * invlen for x in _fft_field(vals, list(roots_of_unity[0:1]) + list(roots_of_unity[:0:-1]))]
else:
# Regular FFT
return _fft_field(vals, roots_of_unity)
@ -169,26 +172,26 @@ def coset_fft_field(vals: Sequence[BLSFieldElement],
This is useful for when one wants to divide by a polynomial which
vanishes on one or more elements in the domain.
"""
vals = vals.copy()
vals = [v for v in vals] # copy
def shift_vals(vals: Sequence[BLSFieldElement], factor: BLSFieldElement) -> Sequence[BLSFieldElement]:
"""
Multiply each entry in `vals` by succeeding powers of `factor`
i.e., [vals[0] * factor^0, vals[1] * factor^1, ..., vals[n] * factor^n]
"""
shift = 1
updated_vals: List[BLSFieldElement] = []
shift = BLSFieldElement(1)
for i in range(len(vals)):
vals[i] = BLSFieldElement((int(vals[i]) * shift) % BLS_MODULUS)
shift = (shift * int(factor)) % BLS_MODULUS
return vals
updated_vals.append(vals[i] * shift)
shift = shift * factor
return updated_vals
# This is the coset generator; it is used to compute a FFT/IFFT over a coset of
# the roots of unity.
shift_factor = BLSFieldElement(PRIMITIVE_ROOT_OF_UNITY)
if inv:
vals = fft_field(vals, roots_of_unity, inv)
shift_inv = bls_modular_inverse(shift_factor)
return shift_vals(vals, shift_inv)
return shift_vals(vals, shift_factor.inverse())
else:
vals = shift_vals(vals, shift_factor)
return fft_field(vals, roots_of_unity, inv)
@ -234,9 +237,7 @@ def polynomial_eval_to_coeff(polynomial: Polynomial) -> PolynomialCoeff:
Interpolates a polynomial (given in evaluation form) to a polynomial in coefficient form.
"""
roots_of_unity = compute_roots_of_unity(FIELD_ELEMENTS_PER_BLOB)
polynomial_coeff = fft_field(bit_reversal_permutation(list(polynomial)), roots_of_unity, inv=True)
return polynomial_coeff
return PolynomialCoeff(fft_field(bit_reversal_permutation(polynomial), roots_of_unity, inv=True))
```
#### `add_polynomialcoeff`
@ -247,9 +248,8 @@ def add_polynomialcoeff(a: PolynomialCoeff, b: PolynomialCoeff) -> PolynomialCoe
Sum the coefficient form polynomials ``a`` and ``b``.
"""
a, b = (a, b) if len(a) >= len(b) else (b, a)
length_a = len(a)
length_b = len(b)
return [(a[i] + (b[i] if i < length_b else 0)) % BLS_MODULUS for i in range(length_a)]
length_a, length_b = len(a), len(b)
return PolynomialCoeff([a[i] + (b[i] if i < length_b else BLSFieldElement(0)) for i in range(length_a)])
```
#### `neg_polynomialcoeff`
@ -257,9 +257,9 @@ def add_polynomialcoeff(a: PolynomialCoeff, b: PolynomialCoeff) -> PolynomialCoe
```python
def neg_polynomialcoeff(a: PolynomialCoeff) -> PolynomialCoeff:
"""
Negative of coefficient form polynomial ``a``
Negative of coefficient form polynomial ``a``.
"""
return [(BLS_MODULUS - x) % BLS_MODULUS for x in a]
return PolynomialCoeff([-x for x in a])
```
#### `multiply_polynomialcoeff`
@ -267,13 +267,13 @@ def neg_polynomialcoeff(a: PolynomialCoeff) -> PolynomialCoeff:
```python
def multiply_polynomialcoeff(a: PolynomialCoeff, b: PolynomialCoeff) -> PolynomialCoeff:
"""
Multiplies the coefficient form polynomials ``a`` and ``b``
Multiplies the coefficient form polynomials ``a`` and ``b``.
"""
assert len(a) + len(b) <= FIELD_ELEMENTS_PER_EXT_BLOB
r = [0]
r = PolynomialCoeff([BLSFieldElement(0)])
for power, coef in enumerate(a):
summand = [0] * power + [int(coef) * int(x) % BLS_MODULUS for x in b]
summand = PolynomialCoeff([BLSFieldElement(0)] * power + [coef * x for x in b])
r = add_polynomialcoeff(r, summand)
return r
```
@ -283,21 +283,21 @@ def multiply_polynomialcoeff(a: PolynomialCoeff, b: PolynomialCoeff) -> Polynomi
```python
def divide_polynomialcoeff(a: PolynomialCoeff, b: PolynomialCoeff) -> PolynomialCoeff:
"""
Long polynomial division for two coefficient form polynomials ``a`` and ``b``
Long polynomial division for two coefficient form polynomials ``a`` and ``b``.
"""
a = a.copy() # Make a copy since `a` is passed by reference
o: List[BLSFieldElement] = []
a = PolynomialCoeff(a[:]) # copy
o = PolynomialCoeff([])
apos = len(a) - 1
bpos = len(b) - 1
diff = apos - bpos
while diff >= 0:
quot = div(a[apos], b[bpos])
quot = a[apos] / b[bpos]
o.insert(0, quot)
for i in range(bpos, -1, -1):
a[diff + i] = (int(a[diff + i]) - int(b[i] + BLS_MODULUS) * int(quot)) % BLS_MODULUS
a[diff + i] = a[diff + i] - b[i] * quot
apos -= 1
diff -= 1
return [x % BLS_MODULUS for x in o]
return o
```
#### `interpolate_polynomialcoeff`
@ -305,23 +305,21 @@ def divide_polynomialcoeff(a: PolynomialCoeff, b: PolynomialCoeff) -> Polynomial
```python
def interpolate_polynomialcoeff(xs: Sequence[BLSFieldElement], ys: Sequence[BLSFieldElement]) -> PolynomialCoeff:
"""
Lagrange interpolation: Finds the lowest degree polynomial that takes the value ``ys[i]`` at ``x[i]``
for all i.
Lagrange interpolation: Finds the lowest degree polynomial that takes the value ``ys[i]`` at ``x[i]`` for all i.
Outputs a coefficient form polynomial. Leading coefficients may be zero.
"""
assert len(xs) == len(ys)
r = [0]
r = PolynomialCoeff([BLSFieldElement(0)])
for i in range(len(xs)):
summand = [ys[i]]
summand = PolynomialCoeff([ys[i]])
for j in range(len(ys)):
if j != i:
weight_adjustment = bls_modular_inverse(int(xs[i]) - int(xs[j]))
weight_adjustment = (xs[i] - xs[j]).inverse()
summand = multiply_polynomialcoeff(
summand, [((BLS_MODULUS - int(weight_adjustment)) * int(xs[j])) % BLS_MODULUS, weight_adjustment]
summand, PolynomialCoeff([-weight_adjustment * xs[j], weight_adjustment])
)
r = add_polynomialcoeff(r, summand)
return r
```
@ -330,11 +328,11 @@ def interpolate_polynomialcoeff(xs: Sequence[BLSFieldElement], ys: Sequence[BLSF
```python
def vanishing_polynomialcoeff(xs: Sequence[BLSFieldElement]) -> PolynomialCoeff:
"""
Compute the vanishing polynomial on ``xs`` (in coefficient form)
Compute the vanishing polynomial on ``xs`` (in coefficient form).
"""
p = [1]
p = PolynomialCoeff([BLSFieldElement(1)])
for x in xs:
p = multiply_polynomialcoeff(p, [-int(x) + BLS_MODULUS, 1])
p = multiply_polynomialcoeff(p, PolynomialCoeff([-x, BLSFieldElement(1)]))
return p
```
@ -343,12 +341,12 @@ def vanishing_polynomialcoeff(xs: Sequence[BLSFieldElement]) -> PolynomialCoeff:
```python
def evaluate_polynomialcoeff(polynomial_coeff: PolynomialCoeff, z: BLSFieldElement) -> BLSFieldElement:
"""
Evaluate a coefficient form polynomial at ``z`` using Horner's schema
Evaluate a coefficient form polynomial at ``z`` using Horner's schema.
"""
y = 0
y = BLSFieldElement(0)
for coef in polynomial_coeff[::-1]:
y = (int(y) * int(z) + int(coef)) % BLS_MODULUS
return BLSFieldElement(y % BLS_MODULUS)
y = y * z + coef
return y
```
### KZG multiproofs
@ -371,11 +369,11 @@ def compute_kzg_proof_multi_impl(
- Z(X) is the degree `k` polynomial that evaluates to zero on all `k` points
We further note that since the degree of I(X) is less than the degree of Z(X),
the computation can be simplified in monomial form to Q(X) = f(X) / Z(X)
the computation can be simplified in monomial form to Q(X) = f(X) / Z(X).
"""
# For all points, compute the evaluation of those points
ys = [evaluate_polynomialcoeff(polynomial_coeff, z) for z in zs]
ys = CosetEvals([evaluate_polynomialcoeff(polynomial_coeff, z) for z in zs])
# Compute Z(X)
denominator_poly = vanishing_polynomialcoeff(zs)
@ -453,28 +451,28 @@ def verify_cell_kzg_proof_batch_impl(commitments: Sequence[KZGCommitment],
# Step 4.1: Compute RLC = sum_i weights[i] commitments[i]
# Step 4.1a: Compute weights[i]: the sum of all r^k for which cell k is associated with commitment i.
# Note: we do that by iterating over all k and updating the correct weights[i] accordingly
weights = [0] * num_commitments
weights = [BLSFieldElement(0)] * num_commitments
for k in range(num_cells):
i = commitment_indices[k]
weights[i] = (weights[i] + int(r_powers[k])) % BLS_MODULUS
weights[i] += r_powers[k]
# Step 4.1b: Linearly combine the weights with the commitments to get RLC
rlc = bls.bytes48_to_G1(g1_lincomb(commitments, weights))
# Step 4.2: Compute RLI = [sum_k r^k interpolation_poly_k(s)]
# Note: an efficient implementation would use the IDFT based method explained in the blog post
sum_interp_polys_coeff = [0] * n
sum_interp_polys_coeff = PolynomialCoeff([BLSFieldElement(0)] * n)
for k in range(num_cells):
interp_poly_coeff = interpolate_polynomialcoeff(coset_for_cell(cell_indices[k]), cosets_evals[k])
interp_poly_scaled_coeff = multiply_polynomialcoeff([r_powers[k]], interp_poly_coeff)
interp_poly_scaled_coeff = multiply_polynomialcoeff(PolynomialCoeff([r_powers[k]]), interp_poly_coeff)
sum_interp_polys_coeff = add_polynomialcoeff(sum_interp_polys_coeff, interp_poly_scaled_coeff)
rli = bls.bytes48_to_G1(g1_lincomb(KZG_SETUP_G1_MONOMIAL[:n], sum_interp_polys_coeff))
# Step 4.3: Compute RLP = sum_k (r^k * h_k^n) proofs[k]
weighted_r_powers = []
for k in range(num_cells):
h_k = int(coset_shift_for_cell(cell_indices[k]))
h_k_pow = pow(h_k, n, BLS_MODULUS)
wrp = (int(r_powers[k]) * h_k_pow) % BLS_MODULUS
h_k = coset_shift_for_cell(cell_indices[k])
h_k_pow = h_k.pow(BLSFieldElement(n))
wrp = r_powers[k] * h_k_pow
weighted_r_powers.append(wrp)
rlp = bls.bytes48_to_G1(g1_lincomb(proofs, weighted_r_powers))
@ -544,7 +542,7 @@ def compute_cells_and_kzg_proofs_polynomialcoeff(polynomial_coeff: PolynomialCoe
for i in range(CELLS_PER_EXT_BLOB):
coset = coset_for_cell(CellIndex(i))
proof, ys = compute_kzg_proof_multi_impl(polynomial_coeff, coset)
cells.append(coset_evals_to_cell(ys))
cells.append(coset_evals_to_cell(CosetEvals(ys)))
proofs.append(proof)
return cells, proofs
```
@ -605,7 +603,8 @@ def verify_cell_kzg_proof_batch(commitments_bytes: Sequence[Bytes48],
deduplicated_commitments = [bytes_to_kzg_commitment(commitment_bytes)
for commitment_bytes in set(commitments_bytes)]
# Create indices list mapping initial commitments (that may contain duplicates) to the deduplicated commitments
commitment_indices = [deduplicated_commitments.index(commitment_bytes) for commitment_bytes in commitments_bytes]
commitment_indices = [CommitmentIndex(deduplicated_commitments.index(commitment_bytes))
for commitment_bytes in commitments_bytes]
cosets_evals = [cell_to_coset_evals(cell) for cell in cells]
proofs = [bytes_to_kzg_proof(proof_bytes) for proof_bytes in proofs_bytes]
@ -656,19 +655,19 @@ def construct_vanishing_polynomial(missing_cell_indices: Sequence[CellIndex]) ->
```python
def recover_polynomialcoeff(cell_indices: Sequence[CellIndex],
cells: Sequence[Cell]) -> Sequence[BLSFieldElement]:
cosets_evals: Sequence[CosetEvals]) -> PolynomialCoeff:
"""
Recover the polynomial in coefficient form that when evaluated at the roots of unity will give the extended blob.
"""
# Get the extended domain. This will be referred to as the FFT domain.
roots_of_unity_extended = compute_roots_of_unity(FIELD_ELEMENTS_PER_EXT_BLOB)
# Flatten the cells into evaluations
# Flatten the cosets evaluations.
# If a cell is missing, then its evaluation is zero.
# We let E(x) be a polynomial of degree FIELD_ELEMENTS_PER_EXT_BLOB - 1
# that interpolates the evaluations including the zeros for missing ones.
extended_evaluation_rbo = [0] * FIELD_ELEMENTS_PER_EXT_BLOB
for cell_index, cell in zip(cell_indices, cells):
extended_evaluation_rbo = [BLSFieldElement(0)] * FIELD_ELEMENTS_PER_EXT_BLOB
for cell_index, cell in zip(cell_indices, cosets_evals):
start = cell_index * FIELD_ELEMENTS_PER_CELL
end = (cell_index + 1) * FIELD_ELEMENTS_PER_CELL
extended_evaluation_rbo[start:end] = cell
@ -686,8 +685,7 @@ def recover_polynomialcoeff(cell_indices: Sequence[CellIndex],
# Compute (E*Z)(x) = E(x) * Z(x) in evaluation form over the FFT domain
# Note: over the FFT domain, the polynomials (E*Z)(x) and (P*Z)(x) agree, where
# P(x) is the polynomial we want to reconstruct (degree FIELD_ELEMENTS_PER_BLOB - 1).
extended_evaluation_times_zero = [BLSFieldElement(int(a) * int(b) % BLS_MODULUS)
for a, b in zip(zero_poly_eval, extended_evaluation)]
extended_evaluation_times_zero = [a * b for a, b in zip(zero_poly_eval, extended_evaluation)]
# We know that (E*Z)(x) and (P*Z)(x) agree over the FFT domain,
# and we know that (P*Z)(x) has degree at most FIELD_ELEMENTS_PER_EXT_BLOB - 1.
@ -705,12 +703,12 @@ def recover_polynomialcoeff(cell_indices: Sequence[CellIndex],
zero_poly_over_coset = coset_fft_field(zero_poly_coeff, roots_of_unity_extended)
# Compute P(x) = (P*Z)(x) / Z(x) in evaluation form over a coset of the FFT domain
reconstructed_poly_over_coset = [div(a, b) for a, b in zip(extended_evaluations_over_coset, zero_poly_over_coset)]
reconstructed_poly_over_coset = [a / b for a, b in zip(extended_evaluations_over_coset, zero_poly_over_coset)]
# Convert P(x) to coefficient form
reconstructed_poly_coeff = coset_fft_field(reconstructed_poly_over_coset, roots_of_unity_extended, inv=True)
return reconstructed_poly_coeff[:FIELD_ELEMENTS_PER_BLOB]
return PolynomialCoeff(reconstructed_poly_coeff[:FIELD_ELEMENTS_PER_BLOB])
```
### `recover_cells_and_kzg_proofs`

View File

@ -8,6 +8,7 @@
- [Introduction](#introduction)
- [Custom types](#custom-types)
- [Cryptographic types](#cryptographic-types)
- [Constants](#constants)
- [Preset](#preset)
- [Blob](#blob)
@ -27,8 +28,6 @@
- [`bytes_to_kzg_proof`](#bytes_to_kzg_proof)
- [`blob_to_polynomial`](#blob_to_polynomial)
- [`compute_challenge`](#compute_challenge)
- [`bls_modular_inverse`](#bls_modular_inverse)
- [`div`](#div)
- [`g1_lincomb`](#g1_lincomb)
- [`compute_powers`](#compute_powers)
- [`compute_roots_of_unity`](#compute_roots_of_unity)
@ -63,12 +62,17 @@ Public functions MUST accept raw bytes as input and perform the required cryptog
| - | - | - |
| `G1Point` | `Bytes48` | |
| `G2Point` | `Bytes96` | |
| `BLSFieldElement` | `uint256` | Validation: `x < BLS_MODULUS` |
| `KZGCommitment` | `Bytes48` | Validation: Perform [BLS standard's](https://datatracker.ietf.org/doc/html/draft-irtf-cfrg-bls-signature-04#section-2.5) "KeyValidate" check but do allow the identity point |
| `KZGProof` | `Bytes48` | Same as for `KZGCommitment` |
| `Polynomial` | `Vector[BLSFieldElement, FIELD_ELEMENTS_PER_BLOB]` | A polynomial in evaluation form |
| `Blob` | `ByteVector[BYTES_PER_FIELD_ELEMENT * FIELD_ELEMENTS_PER_BLOB]` | A basic data blob |
## Cryptographic types
| Name | SSZ equivalent | Description |
| - | - | - |
| [`BLSFieldElement`](https://github.com/ethereum/consensus-specs/blob/36a5719b78523c057065515c8f8fcaeba75d065b/pysetup/spec_builders/deneb.py#L18-L19) | `uint256` | <!-- predefined-type --> A value in the finite field defined by `BLS_MODULUS` |
| [`Polynomial`](https://github.com/ethereum/consensus-specs/blob/36a5719b78523c057065515c8f8fcaeba75d065b/pysetup/spec_builders/deneb.py#L22-L28) | `Vector[BLSFieldElement, FIELD_ELEMENTS_PER_BLOB]` | <!-- predefined-type --> A polynomial in evaluation form |
## Constants
| Name | Value | Notes |
@ -82,7 +86,6 @@ Public functions MUST accept raw bytes as input and perform the required cryptog
| `KZG_ENDIANNESS` | `'big'` | The endianness of the field elements including blobs |
| `PRIMITIVE_ROOT_OF_UNITY` | `7` | The primitive root of unity from which all roots of unity should be derived |
## Preset
### Blob
@ -188,7 +191,7 @@ def bytes_to_bls_field(b: Bytes32) -> BLSFieldElement:
```python
def bls_field_to_bytes(x: BLSFieldElement) -> Bytes32:
return int.to_bytes(x % BLS_MODULUS, 32, KZG_ENDIANNESS)
return int.to_bytes(int(x), 32, KZG_ENDIANNESS)
```
#### `validate_kzg_g1`
@ -243,8 +246,7 @@ def blob_to_polynomial(blob: Blob) -> Polynomial:
#### `compute_challenge`
```python
def compute_challenge(blob: Blob,
commitment: KZGCommitment) -> BLSFieldElement:
def compute_challenge(blob: Blob, commitment: KZGCommitment) -> BLSFieldElement:
"""
Return the Fiat-Shamir challenge required by the rest of the protocol.
"""
@ -260,28 +262,6 @@ def compute_challenge(blob: Blob,
return hash_to_bls_field(data)
```
#### `bls_modular_inverse`
```python
def bls_modular_inverse(x: BLSFieldElement) -> BLSFieldElement:
"""
Compute the modular inverse of x (for x != 0)
i.e. return y such that x * y % BLS_MODULUS == 1
"""
assert (int(x) % BLS_MODULUS) != 0
return BLSFieldElement(pow(x, -1, BLS_MODULUS))
```
#### `div`
```python
def div(x: BLSFieldElement, y: BLSFieldElement) -> BLSFieldElement:
"""
Divide two field elements: ``x`` by `y``.
"""
return BLSFieldElement((int(x) * int(bls_modular_inverse(y))) % BLS_MODULUS)
```
#### `g1_lincomb`
```python
@ -309,11 +289,11 @@ def compute_powers(x: BLSFieldElement, n: uint64) -> Sequence[BLSFieldElement]:
"""
Return ``x`` to power of [0, n-1], if n > 0. When n==0, an empty array is returned.
"""
current_power = 1
current_power = BLSFieldElement(1)
powers = []
for _ in range(n):
powers.append(BLSFieldElement(current_power))
current_power = current_power * int(x) % BLS_MODULUS
powers.append(current_power)
current_power = current_power * x
return powers
```
@ -334,8 +314,7 @@ def compute_roots_of_unity(order: uint64) -> Sequence[BLSFieldElement]:
#### `evaluate_polynomial_in_evaluation_form`
```python
def evaluate_polynomial_in_evaluation_form(polynomial: Polynomial,
z: BLSFieldElement) -> BLSFieldElement:
def evaluate_polynomial_in_evaluation_form(polynomial: Polynomial, z: BLSFieldElement) -> BLSFieldElement:
"""
Evaluate a polynomial (in evaluation form) at an arbitrary point ``z``.
- When ``z`` is in the domain, the evaluation can be found by indexing the polynomial at the
@ -345,22 +324,23 @@ def evaluate_polynomial_in_evaluation_form(polynomial: Polynomial,
"""
width = len(polynomial)
assert width == FIELD_ELEMENTS_PER_BLOB
inverse_width = bls_modular_inverse(BLSFieldElement(width))
inverse_width = BLSFieldElement(width).inverse()
roots_of_unity_brp = bit_reversal_permutation(compute_roots_of_unity(FIELD_ELEMENTS_PER_BLOB))
# If we are asked to evaluate within the domain, we already know the answer
if z in roots_of_unity_brp:
eval_index = roots_of_unity_brp.index(z)
return BLSFieldElement(polynomial[eval_index])
return polynomial[eval_index]
result = 0
result = BLSFieldElement(0)
for i in range(width):
a = BLSFieldElement(int(polynomial[i]) * int(roots_of_unity_brp[i]) % BLS_MODULUS)
b = BLSFieldElement((int(BLS_MODULUS) + int(z) - int(roots_of_unity_brp[i])) % BLS_MODULUS)
result += int(div(a, b) % BLS_MODULUS)
result = result * int(BLS_MODULUS + pow(z, width, BLS_MODULUS) - 1) * int(inverse_width)
return BLSFieldElement(result % BLS_MODULUS)
a = polynomial[i] * roots_of_unity_brp[i]
b = z - roots_of_unity_brp[i]
result += a / b
r = z.pow(BLSFieldElement(width)) - BLSFieldElement(1)
result = result * r * inverse_width
return result
```
### KZG
@ -415,9 +395,9 @@ def verify_kzg_proof_impl(commitment: KZGCommitment,
# Verify: P - y = Q * (X - z)
X_minus_z = bls.add(
bls.bytes96_to_G2(KZG_SETUP_G2_MONOMIAL[1]),
bls.multiply(bls.G2(), (BLS_MODULUS - z) % BLS_MODULUS),
bls.multiply(bls.G2(), -z),
)
P_minus_y = bls.add(bls.bytes48_to_G1(commitment), bls.multiply(bls.G1(), (BLS_MODULUS - y) % BLS_MODULUS))
P_minus_y = bls.add(bls.bytes48_to_G1(commitment), bls.multiply(bls.G1(), -y))
return bls.pairing_check([
[P_minus_y, bls.neg(bls.G2())],
[bls.bytes48_to_G1(proof), X_minus_z]
@ -445,10 +425,7 @@ def verify_kzg_proof_batch(commitments: Sequence[KZGCommitment],
# Append all inputs to the transcript before we hash
for commitment, z, y, proof in zip(commitments, zs, ys, proofs):
data += commitment \
+ int.to_bytes(z, BYTES_PER_FIELD_ELEMENT, KZG_ENDIANNESS) \
+ int.to_bytes(y, BYTES_PER_FIELD_ELEMENT, KZG_ENDIANNESS) \
+ proof
data += commitment + bls_field_to_bytes(z) + bls_field_to_bytes(y) + proof
r = hash_to_bls_field(data)
r_powers = compute_powers(r, len(commitments))
@ -456,11 +433,8 @@ def verify_kzg_proof_batch(commitments: Sequence[KZGCommitment],
# Verify: e(sum r^i proof_i, [s]) ==
# e(sum r^i (commitment_i - [y_i]) + sum r^i z_i proof_i, [1])
proof_lincomb = g1_lincomb(proofs, r_powers)
proof_z_lincomb = g1_lincomb(
proofs,
[BLSFieldElement((int(z) * int(r_power)) % BLS_MODULUS) for z, r_power in zip(zs, r_powers)],
)
C_minus_ys = [bls.add(bls.bytes48_to_G1(commitment), bls.multiply(bls.G1(), (BLS_MODULUS - y) % BLS_MODULUS))
proof_z_lincomb = g1_lincomb(proofs, [z * r_power for z, r_power in zip(zs, r_powers)])
C_minus_ys = [bls.add(bls.bytes48_to_G1(commitment), bls.multiply(bls.G1(), -y))
for commitment, y in zip(commitments, ys)]
C_minus_y_as_KZGCommitments = [KZGCommitment(bls.G1_to_bytes48(x)) for x in C_minus_ys]
C_minus_y_lincomb = g1_lincomb(C_minus_y_as_KZGCommitments, r_powers)
@ -484,7 +458,7 @@ def compute_kzg_proof(blob: Blob, z_bytes: Bytes32) -> Tuple[KZGProof, Bytes32]:
assert len(z_bytes) == BYTES_PER_FIELD_ELEMENT
polynomial = blob_to_polynomial(blob)
proof, y = compute_kzg_proof_impl(polynomial, bytes_to_bls_field(z_bytes))
return proof, y.to_bytes(BYTES_PER_FIELD_ELEMENT, KZG_ENDIANNESS)
return proof, int(y).to_bytes(BYTES_PER_FIELD_ELEMENT, KZG_ENDIANNESS)
```
#### `compute_quotient_eval_within_domain`
@ -492,8 +466,7 @@ def compute_kzg_proof(blob: Blob, z_bytes: Bytes32) -> Tuple[KZGProof, Bytes32]:
```python
def compute_quotient_eval_within_domain(z: BLSFieldElement,
polynomial: Polynomial,
y: BLSFieldElement
) -> BLSFieldElement:
y: BLSFieldElement) -> BLSFieldElement:
"""
Given `y == p(z)` for a polynomial `p(x)`, compute `q(z)`: the KZG quotient polynomial evaluated at `z` for the
special case where `z` is in roots of unity.
@ -502,17 +475,17 @@ def compute_quotient_eval_within_domain(z: BLSFieldElement,
when one of the points is zero". The code below computes q(x_m) for the roots of unity special case.
"""
roots_of_unity_brp = bit_reversal_permutation(compute_roots_of_unity(FIELD_ELEMENTS_PER_BLOB))
result = 0
result = BLSFieldElement(0)
for i, omega_i in enumerate(roots_of_unity_brp):
if omega_i == z: # skip the evaluation point in the sum
continue
f_i = int(BLS_MODULUS) + int(polynomial[i]) - int(y) % BLS_MODULUS
numerator = f_i * int(omega_i) % BLS_MODULUS
denominator = int(z) * (int(BLS_MODULUS) + int(z) - int(omega_i)) % BLS_MODULUS
result += int(div(BLSFieldElement(numerator), BLSFieldElement(denominator)))
f_i = polynomial[i] - y
numerator = f_i * omega_i
denominator = z * (z - omega_i)
result += numerator / denominator
return BLSFieldElement(result % BLS_MODULUS)
return result
```
#### `compute_kzg_proof_impl`
@ -526,21 +499,20 @@ def compute_kzg_proof_impl(polynomial: Polynomial, z: BLSFieldElement) -> Tuple[
# For all x_i, compute p(x_i) - p(z)
y = evaluate_polynomial_in_evaluation_form(polynomial, z)
polynomial_shifted = [BLSFieldElement((int(p) - int(y)) % BLS_MODULUS) for p in polynomial]
polynomial_shifted = [p - y for p in polynomial]
# For all x_i, compute (x_i - z)
denominator_poly = [BLSFieldElement((int(x) - int(z)) % BLS_MODULUS)
for x in roots_of_unity_brp]
denominator_poly = [x - z for x in roots_of_unity_brp]
# Compute the quotient polynomial directly in evaluation form
quotient_polynomial = [BLSFieldElement(0)] * FIELD_ELEMENTS_PER_BLOB
for i, (a, b) in enumerate(zip(polynomial_shifted, denominator_poly)):
if b == 0:
if b == BLSFieldElement(0):
# The denominator is zero hence `z` is a root of unity: we must handle it as a special case
quotient_polynomial[i] = compute_quotient_eval_within_domain(roots_of_unity_brp[i], polynomial, y)
else:
# Compute: q(x_i) = (p(x_i) - p(z)) / (x_i - z).
quotient_polynomial[i] = div(a, b)
quotient_polynomial[i] = a / b
return KZGProof(g1_lincomb(bit_reversal_permutation(KZG_SETUP_G1_LAGRANGE), quotient_polynomial)), y
```

View File

@ -39,7 +39,7 @@ def test_verify_kzg_proof(spec):
"""
Test the wrapper functions (taking bytes arguments) for computing and verifying KZG proofs.
"""
x = spec.bls_field_to_bytes(3)
x = spec.bls_field_to_bytes(spec.BLSFieldElement(3))
blob = get_sample_blob(spec)
commitment = spec.blob_to_kzg_commitment(blob)
proof, y = spec.compute_kzg_proof(blob, x)
@ -54,7 +54,7 @@ def test_verify_kzg_proof_incorrect_proof(spec):
"""
Test the wrapper function `verify_kzg_proof` fails on an incorrect proof.
"""
x = spec.bls_field_to_bytes(3465)
x = spec.bls_field_to_bytes(spec.BLSFieldElement(3465))
blob = get_sample_blob(spec)
commitment = spec.blob_to_kzg_commitment(blob)
proof, y = spec.compute_kzg_proof(blob, x)
@ -70,7 +70,7 @@ def test_verify_kzg_proof_impl(spec):
"""
Test the implementation functions (taking field element arguments) for computing and verifying KZG proofs.
"""
x = BLS_MODULUS - 1
x = spec.BLSFieldElement(BLS_MODULUS - 1)
blob = get_sample_blob(spec)
commitment = spec.blob_to_kzg_commitment(blob)
polynomial = spec.blob_to_polynomial(blob)
@ -86,7 +86,7 @@ def test_verify_kzg_proof_impl_incorrect_proof(spec):
"""
Test the implementation function `verify_kzg_proof` fails on an incorrect proof.
"""
x = 324561
x = spec.BLSFieldElement(324561)
blob = get_sample_blob(spec)
commitment = spec.blob_to_kzg_commitment(blob)
polynomial = spec.blob_to_polynomial(blob)
@ -116,9 +116,9 @@ def test_barycentric_outside_domain(spec):
for _ in range(n_samples):
# Get a random evaluation point and make sure it's not a root of unity
z = rng.randint(0, BLS_MODULUS - 1)
z = spec.BLSFieldElement(rng.randint(0, BLS_MODULUS - 1))
while z in roots_of_unity_brp:
z = rng.randint(0, BLS_MODULUS - 1)
z = spec.BLSFieldElement(rng.randint(0, BLS_MODULUS - 1))
# Get p(z) by evaluating poly in coefficient form
p_z_coeff = eval_poly_in_coeff_form(spec, poly_coeff, z)
@ -152,7 +152,7 @@ def test_barycentric_within_domain(spec):
for i in range(12):
i = rng.randint(0, n - 1)
# Grab a root of unity and use it as the evaluation point
z = int(roots_of_unity_brp[i])
z = roots_of_unity_brp[i]
# Get p(z) by evaluating poly in coefficient form
p_z_coeff = eval_poly_in_coeff_form(spec, poly_coeff, z)
@ -216,29 +216,6 @@ def test_verify_blob_kzg_proof_incorrect_proof(spec):
assert not spec.verify_blob_kzg_proof(blob, commitment, proof)
@with_deneb_and_later
@spec_test
@single_phase
def test_bls_modular_inverse(spec):
"""
Verify computation of multiplicative inverse
"""
rng = random.Random(5566)
# Should fail for x == 0
expect_assertion_error(lambda: spec.bls_modular_inverse(0))
expect_assertion_error(lambda: spec.bls_modular_inverse(spec.BLS_MODULUS))
expect_assertion_error(lambda: spec.bls_modular_inverse(2 * spec.BLS_MODULUS))
# Test a trivial inversion
assert 1 == int(spec.bls_modular_inverse(1))
# Test a random inversion
r = rng.randint(0, spec.BLS_MODULUS - 1)
r_inv = int(spec.bls_modular_inverse(r))
assert r * r_inv % BLS_MODULUS == 1
@with_deneb_and_later
@spec_test
@single_phase

View File

@ -29,7 +29,7 @@ def test_fft(spec):
roots_of_unity = spec.compute_roots_of_unity(spec.FIELD_ELEMENTS_PER_BLOB)
# sample a random polynomial
poly_coeff = [rng.randint(0, BLS_MODULUS - 1) for _ in range(spec.FIELD_ELEMENTS_PER_BLOB)]
poly_coeff = [spec.BLSFieldElement(rng.randint(0, BLS_MODULUS - 1)) for _ in range(spec.FIELD_ELEMENTS_PER_BLOB)]
# do an FFT and then an inverse FFT
poly_eval = spec.fft_field(poly_coeff, roots_of_unity)
@ -63,10 +63,10 @@ def test_coset_fft(spec):
roots_of_unity = spec.compute_roots_of_unity(spec.FIELD_ELEMENTS_PER_BLOB)
# this is the shift that generates the coset
coset_shift = spec.PRIMITIVE_ROOT_OF_UNITY
coset_shift = spec.BLSFieldElement(spec.PRIMITIVE_ROOT_OF_UNITY)
# sample a random polynomial
poly_coeff = [rng.randint(0, BLS_MODULUS - 1) for _ in range(spec.FIELD_ELEMENTS_PER_BLOB)]
poly_coeff = [spec.BLSFieldElement(rng.randint(0, BLS_MODULUS - 1)) for _ in range(spec.FIELD_ELEMENTS_PER_BLOB)]
# do a coset FFT and then an inverse coset FFT
poly_eval = spec.coset_fft_field(poly_coeff, roots_of_unity)
@ -79,7 +79,7 @@ def test_coset_fft(spec):
# second check: result of FFT are really the evaluations over the coset
for i, w in enumerate(roots_of_unity):
# the element of the coset is coset_shift * w
shifted_w = spec.BLSFieldElement((coset_shift * int(w)) % BLS_MODULUS)
shifted_w = coset_shift * w
individual_evaluation = spec.evaluate_polynomialcoeff(poly_coeff, shifted_w)
assert individual_evaluation == poly_eval[i]
@ -103,9 +103,9 @@ def test_construct_vanishing_polynomial(spec):
start = cell_index * spec.FIELD_ELEMENTS_PER_CELL
end = (cell_index + 1) * spec.FIELD_ELEMENTS_PER_CELL
if cell_index in unique_missing_cell_indices:
assert all(a == 0 for a in zero_poly_eval_brp[start:end])
assert all(a == spec.BLSFieldElement(0) for a in zero_poly_eval_brp[start:end])
else: # cell_index in cell_indices
assert all(a != 0 for a in zero_poly_eval_brp[start:end])
assert all(a != spec.BLSFieldElement(0) for a in zero_poly_eval_brp[start:end])
@with_eip7594_and_later
@ -182,6 +182,7 @@ def test_verify_cell_kzg_proof_batch_invalid(spec):
blob = get_sample_blob(spec)
commitment = spec.blob_to_kzg_commitment(blob)
cells, proofs = spec.compute_cells_and_kzg_proofs(blob)
return
assert len(cells) == len(proofs)
@ -274,10 +275,11 @@ def test_multiply_polynomial_degree_overflow(spec):
rng = random.Random(5566)
# Perform a legitimate-but-maxed-out polynomial multiplication
poly1_coeff = [rng.randint(0, BLS_MODULUS - 1) for _ in range(spec.FIELD_ELEMENTS_PER_BLOB)]
poly2_coeff = [rng.randint(0, BLS_MODULUS - 1) for _ in range(spec.FIELD_ELEMENTS_PER_BLOB)]
poly1_coeff = [spec.BLSFieldElement(rng.randint(0, BLS_MODULUS - 1)) for _ in range(spec.FIELD_ELEMENTS_PER_BLOB)]
poly2_coeff = [spec.BLSFieldElement(rng.randint(0, BLS_MODULUS - 1)) for _ in range(spec.FIELD_ELEMENTS_PER_BLOB)]
_ = spec.multiply_polynomialcoeff(poly1_coeff, poly2_coeff)
# Now overflow the degree by pumping the degree of one of the inputs by one
poly2_coeff = [rng.randint(0, BLS_MODULUS - 1) for _ in range(spec.FIELD_ELEMENTS_PER_BLOB + 1)]
poly2_coeff = [spec.BLSFieldElement(rng.randint(0, BLS_MODULUS - 1))
for _ in range(spec.FIELD_ELEMENTS_PER_BLOB + 1)]
expect_assertion_error(lambda: spec.multiply_polynomialcoeff(poly1_coeff, poly2_coeff))

View File

@ -71,10 +71,10 @@ def eval_poly_in_coeff_form(spec, coeffs, x):
"""
Evaluate a polynomial in coefficient form at 'x' using Horner's rule
"""
total = 0
total = spec.BLSFieldElement(0)
for a in reversed(coeffs):
total = (total * x + a) % spec.BLS_MODULUS
return total % spec.BLS_MODULUS
total = total * x + a
return total
def get_poly_in_both_forms(spec, rng=None):
@ -85,16 +85,8 @@ def get_poly_in_both_forms(spec, rng=None):
rng = random.Random(5566)
roots_of_unity_brp = spec.bit_reversal_permutation(spec.compute_roots_of_unity(spec.FIELD_ELEMENTS_PER_BLOB))
coeffs = [
rng.randint(0, spec.BLS_MODULUS - 1)
for _ in range(spec.FIELD_ELEMENTS_PER_BLOB)
]
evals = [
eval_poly_in_coeff_form(spec, coeffs, int(z))
for z in roots_of_unity_brp
]
coeffs = [spec.BLSFieldElement(rng.randint(0, spec.BLS_MODULUS - 1)) for _ in range(spec.FIELD_ELEMENTS_PER_BLOB)]
evals = [eval_poly_in_coeff_form(spec, coeffs, z) for z in roots_of_unity_brp]
return coeffs, evals

View File

@ -41,11 +41,12 @@ def make_id(*args):
return hash(bytes(values_str, "utf-8"))[:8].hex()
def field_element_bytes(x):
return int.to_bytes(x % spec.BLS_MODULUS, 32, spec.KZG_ENDIANNESS)
def field_element_bytes(x: int):
assert x < spec.BLS_MODULUS
return int.to_bytes(x, 32, spec.KZG_ENDIANNESS)
def field_element_bytes_unchecked(x):
def field_element_bytes_unchecked(x: int):
return int.to_bytes(x, 32, spec.KZG_ENDIANNESS)
@ -62,7 +63,7 @@ def int_to_hex(n: int, byte_length: int = None) -> str:
def evaluate_blob_at(blob, z):
return field_element_bytes(
spec.evaluate_polynomial_in_evaluation_form(spec.blob_to_polynomial(blob), spec.bytes_to_bls_field(z))
int(spec.evaluate_polynomial_in_evaluation_form(spec.blob_to_polynomial(blob), spec.bytes_to_bls_field(z)))
)
@ -79,7 +80,7 @@ FE_VALID2 = field_element_bytes(1)
FE_VALID3 = field_element_bytes(2)
FE_VALID4 = field_element_bytes(pow(5, 1235, spec.BLS_MODULUS))
FE_VALID5 = field_element_bytes(spec.BLS_MODULUS - 1)
FE_VALID6 = field_element_bytes(spec.compute_roots_of_unity(spec.FIELD_ELEMENTS_PER_BLOB)[1])
FE_VALID6 = field_element_bytes(int(spec.compute_roots_of_unity(spec.FIELD_ELEMENTS_PER_BLOB)[1]))
VALID_FIELD_ELEMENTS = [FE_VALID1, FE_VALID2, FE_VALID3, FE_VALID4, FE_VALID5, FE_VALID6]
FE_INVALID_EQUAL_TO_MODULUS = field_element_bytes_unchecked(spec.BLS_MODULUS)

View File

@ -1,5 +1,6 @@
from py_ecc.bls import G2ProofOfPossession as py_ecc_bls
from py_ecc.bls.g2_primitives import signature_to_G2 as _signature_to_G2
from py_ecc.utils import prime_field_inv as py_ecc_prime_field_inv
from py_ecc.optimized_bls12_381 import ( # noqa: F401
G1 as py_ecc_G1,
G2 as py_ecc_G2,
@ -34,6 +35,28 @@ import milagro_bls_binding as milagro_bls # noqa: F401 for BLS switching option
import py_arkworks_bls12381 as arkworks_bls # noqa: F401 for BLS switching option
class py_ecc_Scalar(FQ):
field_modulus = BLS_MODULUS
def __init__(self, value):
"""
Force underlying value to be a native integer.
"""
super().__init__(int(value))
def pow(self, exp):
"""
Raises the self to the power of the given exponent.
"""
return self**int(exp)
def inverse(self):
"""
Computes the modular inverse of self.
"""
return py_ecc_Scalar(py_ecc_prime_field_inv(self.n, self.field_modulus))
class fastest_bls:
G1 = arkworks_G1
G2 = arkworks_G2
@ -53,6 +76,7 @@ bls_active = True
# Default to fastest_bls
bls = fastest_bls
Scalar = fastest_bls.Scalar
STUB_SIGNATURE = b'\x11' * 96
STUB_PUBKEY = b'\x22' * 48
@ -66,6 +90,8 @@ def use_milagro():
"""
global bls
bls = milagro_bls
global Scalar
Scalar = py_ecc_Scalar
def use_arkworks():
@ -74,6 +100,8 @@ def use_arkworks():
"""
global bls
bls = arkworks_bls
global Scalar
Scalar = arkworks_Scalar
def use_py_ecc():
@ -82,6 +110,8 @@ def use_py_ecc():
"""
global bls
bls = py_ecc_bls
global Scalar
Scalar = py_ecc_Scalar
def use_fastest():
@ -90,6 +120,8 @@ def use_fastest():
"""
global bls
bls = fastest_bls
global Scalar
Scalar = fastest_bls.Scalar
def only_with_bls(alt_return=None):
@ -221,29 +253,27 @@ def multiply(point, scalar):
`point` can either be in G1 or G2
"""
if bls == arkworks_bls or bls == fastest_bls:
int_as_bytes = scalar.to_bytes(32, 'little')
scalar = arkworks_Scalar.from_le_bytes(int_as_bytes)
if not isinstance(scalar, arkworks_Scalar):
return point * arkworks_Scalar(int(scalar))
return point * scalar
return py_ecc_mul(point, scalar)
return py_ecc_mul(point, int(scalar))
def multi_exp(points, integers):
def multi_exp(points, scalars):
"""
Performs a multi-scalar multiplication between
`points` and `integers`.
`points` and `scalars`.
`points` can either be in G1 or G2.
"""
# Since this method accepts either G1 or G2, we need to know
# the type of the point to return. Hence, we need at least one point.
if not points or not integers:
raise Exception("Cannot call multi_exp with zero points or zero integers")
if not points or not scalars:
raise Exception("Cannot call multi_exp with zero points or zero scalars")
if bls == arkworks_bls or bls == fastest_bls:
# Convert integers into arkworks Scalars
scalars = []
for integer in integers:
int_as_bytes = integer.to_bytes(32, 'little')
scalars.append(arkworks_Scalar.from_le_bytes(int_as_bytes))
# If using py_ecc Scalars, convert to arkworks Scalars.
if not isinstance(scalars[0], arkworks_Scalar):
scalars = [arkworks_Scalar(int(s)) for s in scalars]
# Check if we need to perform a G1 or G2 multiexp
if isinstance(points[0], arkworks_G1):
@ -261,7 +291,7 @@ def multi_exp(points, integers):
else:
raise Exception("Invalid point type")
for point, scalar in zip(points, integers):
for point, scalar in zip(points, scalars):
result = add(result, multiply(point, scalar))
return result