def from_bytes(cls,
data: bytes,
curve: Optional[Curve] = None) -> 'CapsuleFrag':
"""
Instantiates a CapsuleFrag object from the serialized data.
"""
curve = curve if curve is not None else default_curve()
bn_size = CurveBN.expected_bytes_length(curve)
point_size = Point.expected_bytes_length(curve)
arguments = {'curve': curve}
splitter = BytestringSplitter(
(Point, point_size, arguments), # point_e1
(Point, point_size, arguments), # point_v1
bn_size, # kfrag_id
(Point, point_size, arguments), # point_precursor
)
components = splitter(data, return_remainder=True)
proof = components.pop() or None
components.append(
CorrectnessProof.from_bytes(proof, curve) if proof else None)
return cls(*components)
def from_bytes(cls, data: bytes, curve: Optional[Curve] = None) -> 'KFrag':
"""
Instantiate a KFrag object from the serialized data.
"""
curve = curve if curve is not None else default_curve()
bn_size = CurveBN.expected_bytes_length(curve)
point_size = Point.expected_bytes_length(curve)
signature_size = Signature.expected_bytes_length(curve)
arguments = {'curve': curve}
splitter = BytestringSplitter(
bn_size, # id
(CurveBN, bn_size, arguments), # bn_key
(Point, point_size, arguments), # point_commitment
(Point, point_size, arguments), # point_precursor
1, # keys_in_signature
(Signature, signature_size, arguments), # signature_for_proxy
(Signature, signature_size, arguments), # signature_for_bob
)
components = splitter(data)
return cls(identifier=components[0],
bn_key=components[1],
point_commitment=components[2],
point_precursor=components[3],
keys_in_signature=components[4],
signature_for_proxy=components[5],
signature_for_bob=components[6])
def raw_bytes_from_point(point: Point, only_y_coord=False) -> bytes:
uncompressed_point_bytes = point.to_bytes(is_compressed=False)
if only_y_coord:
y_coord_start = (1 + Point.expected_bytes_length(is_compressed=False)) // 2
return uncompressed_point_bytes[y_coord_start:]
else:
return uncompressed_point_bytes[1:]
def from_bytes(cls, capsule_bytes: bytes, params: UmbralParameters):
"""
Instantiates a Capsule object from the serialized data.
"""
curve = params.curve
bn_size = CurveBN.expected_bytes_length(curve)
point_size = Point.expected_bytes_length(curve)
capsule_bytes_length = len(capsule_bytes)
if capsule_bytes_length == cls.expected_bytes_length(curve,
activated=True):
splitter = BytestringSplitter(
(Point, point_size), # point_e
(Point, point_size), # point_v
(CurveBN, bn_size), # bn_sig
(Point, point_size), # point_e_prime
(Point, point_size), # point_v_prime
(Point, point_size) # point_noninteractive
)
elif capsule_bytes_length == cls.expected_bytes_length(
curve, activated=False):
splitter = BytestringSplitter(
(Point, point_size), # point_e
(Point, point_size), # point_v
(CurveBN, bn_size) # bn_sig
)
else:
raise ValueError(
"Byte string does not have a valid length for a Capsule")
components = splitter(capsule_bytes)
return cls(params, *components)
def from_bytes(cls, capsule_bytes: bytes, curve: ec.EllipticCurve = None):
"""
Instantiates a Capsule object from the serialized data.
"""
curve = curve if curve is not None else default_curve()
bn_size = CurveBN.expected_bytes_length(curve)
point_size = Point.expected_bytes_length(curve)
if len(capsule_bytes) == cls.expected_bytes_length(curve,
activated=True):
splitter = BytestringSplitter(
(Point, point_size), # point_e
(Point, point_size), # point_v
(CurveBN, bn_size), # bn_sig
(Point, point_size), # point_e_prime
(Point, point_size), # point_v_prime
(Point, point_size) # point_noninteractive
)
else:
splitter = BytestringSplitter(
(Point, point_size), # point_e
(Point, point_size), # point_v
(CurveBN, bn_size) # bn_sig
)
components = splitter(capsule_bytes)
return cls(*components)
def expected_bytes_length(cls, curve: Optional[Curve] = None,
is_compressed: bool = True) -> int:
"""
Returns the size (in bytes) of an UmbralPublicKey given a curve.
If no curve is provided, it uses the default curve.
By default, it assumes compressed representation (is_compressed = True).
"""
return Point.expected_bytes_length(curve=curve, is_compressed=is_compressed)
def test_public_key_to_uncompressed_bytes(random_ec_curvebn1):
priv_key = random_ec_curvebn1
params = default_params()
pub_key = priv_key * params.g
umbral_key = UmbralPublicKey(pub_key, params)
key_bytes = umbral_key.to_bytes(is_compressed=False)
assert len(key_bytes) == Point.expected_bytes_length(is_compressed=False)
def expected_bytes_length(cls, curve: Optional[Curve] = None) -> int:
"""
Returns the size (in bytes) of a Capsule given the curve.
If no curve is provided, it will use the default curve.
"""
curve = curve if curve is not None else default_curve()
bn_size = CurveBN.expected_bytes_length(curve)
point_size = Point.expected_bytes_length(curve)
return (bn_size * 1) + (point_size * 2)
def expected_bytes_length(cls, curve: ec.EllipticCurve = None):
"""
Returns the size (in bytes) of a KFrag given the curve.
If no curve is provided, it will use the default curve.
"""
curve = curve if curve is not None else default_curve()
bn_size = CurveBN.expected_bytes_length(curve)
point_size = Point.expected_bytes_length(curve)
return (bn_size * 4) + (point_size * 3)
def expected_bytes_length(cls, curve: Optional[Curve] = None):
"""
Returns the size (in bytes) of a CorrectnessProof without the metadata.
If no curve is given, it will use the default curve.
"""
curve = curve if curve is not None else default_curve()
bn_size = CurveBN.expected_bytes_length(curve=curve)
point_size = Point.expected_bytes_length(curve=curve)
return (bn_size * 3) + (point_size * 4)
def expected_bytes_length(cls,
curve: Optional[EllipticCurve] = None) -> int:
"""
Returns the size (in bytes) of a CapsuleFrag given the curve without
the CorrectnessProof.
If no curve is provided, it will use the default curve.
"""
curve = curve if curve is not None else default_curve()
bn_size = CurveBN.expected_bytes_length(curve)
point_size = Point.expected_bytes_length(curve)
return (bn_size * 1) + (point_size * 4)
def expected_bytes_length(cls,
curve: ec.EllipticCurve = None,
activated=False):
"""
Returns the size (in bytes) of a Capsule given the curve.
If no curve is provided, it will use the default curve.
"""
curve = curve if curve is not None else default_curve()
bn_size = CurveBN.expected_bytes_length(curve)
point_size = Point.expected_bytes_length(curve)
if not activated:
return (bn_size * 1) + (point_size * 2)
else:
return (bn_size * 1) + (point_size * 5)
def expected_bytes_length(cls, curve: Optional[Curve] = None) -> int:
"""
Returns the size (in bytes) of a KFrag given the curve.
If no curve is provided, it will use the default curve.
"""
curve = curve if curve is not None else default_curve()
bn_size = CurveBN.expected_bytes_length(curve)
point_size = Point.expected_bytes_length(curve)
# self.id --> 1 bn_size
# self.bn_key --> 1 bn_size
# self.point_commitment --> 1 point_size
# self.point_precursor --> 1 point_size
# self.signature_for_proxy --> 2 bn_size
# self.signature_for_bob --> 2 bn_size
# self.keys_in_signature --> 1
return bn_size * 6 + point_size * 2 + 1
def from_bytes(cls, data: bytes, curve: ec.EllipticCurve = None):
"""
Instantiate a KFrag object from the serialized data.
"""
curve = curve if curve is not None else default_curve()
bn_size = CurveBN.expected_bytes_length(curve)
point_size = Point.expected_bytes_length(curve)
splitter = BytestringSplitter(
bn_size, # id
(CurveBN, bn_size), # bn_key
(Point, point_size), # point_noninteractive
(Point, point_size), # point_commitment
(Point, point_size), # point_xcoord
(Signature, Signature.expected_bytes_length(curve)))
components = splitter(data)
return cls(*components)
def from_bytes(cls, data: bytes, curve: ec.EllipticCurve = None):
"""
Instantiate CorrectnessProof from serialized data.
"""
curve = curve if curve is not None else default_curve()
bn_size = CurveBN.expected_bytes_length(curve)
point_size = Point.expected_bytes_length(curve)
splitter = BytestringSplitter(
(Point, point_size), # point_e2
(Point, point_size), # point_v2
(Point, point_size), # point_kfrag_commitment
(Point, point_size), # point_kfrag_pok
(CurveBN, bn_size), # bn_sig
(Signature), # kfrag_signature
)
components = splitter(data, return_remainder=True)
metadata = components.pop(-1) or None
return cls(*components, metadata=metadata)
def from_bytes(cls, data: bytes, curve: Optional[Curve] = None) -> 'CorrectnessProof':
"""
Instantiate CorrectnessProof from serialized data.
"""
curve = curve if curve is not None else default_curve()
bn_size = CurveBN.expected_bytes_length(curve)
point_size = Point.expected_bytes_length(curve)
arguments = {'curve': curve}
splitter = BytestringSplitter(
(Point, point_size, arguments), # point_e2
(Point, point_size, arguments), # point_v2
(Point, point_size, arguments), # point_kfrag_commitment
(Point, point_size, arguments), # point_kfrag_pok
(CurveBN, bn_size, arguments), # bn_sig
(Signature, Signature.expected_bytes_length(curve), arguments), # kfrag_signature
)
components = splitter(data, return_remainder=True)
components.append(components.pop() or None)
return cls(*components)
def from_bytes(cls, data: bytes, curve: ec.EllipticCurve = None):
"""
Instantiates a CapsuleFrag object from the serialized data.
"""
curve = curve if curve is not None else default_curve()
bn_size = CurveBN.expected_bytes_length(curve)
point_size = Point.expected_bytes_length(curve)
splitter = BytestringSplitter(
(Point, point_size), # point_e1
(Point, point_size), # point_v1
bn_size, # kfrag_id
(Point, point_size), # point_noninteractive
(Point, point_size) # point_xcoord
)
components = splitter(data, return_remainder=True)
proof = components.pop(-1) or None
proof = CorrectnessProof.from_bytes(proof, curve) if proof else None
return cls(*components, proof)
def from_bytes(cls, capsule_bytes: bytes,
params: UmbralParameters) -> 'Capsule':
"""
Instantiates a Capsule object from the serialized data.
"""
curve = params.curve
bn_size = CurveBN.expected_bytes_length(curve)
point_size = Point.expected_bytes_length(curve)
arguments = {'curve': curve}
if len(capsule_bytes) == cls.expected_bytes_length(curve):
splitter = BytestringSplitter(
(Point, point_size, arguments), # point_e
(Point, point_size, arguments), # point_v
(CurveBN, bn_size, arguments) # bn_sig
)
else:
raise ValueError(
"Byte string does not have a valid length for a Capsule")
components = splitter(capsule_bytes)
return cls(params, *components)
def test_public_key_to_compressed_bytes(random_ec_curvebn1):
umbral_key = UmbralPrivateKey(random_ec_curvebn1, default_params()).get_pubkey()
key_bytes = bytes(umbral_key)
assert len(key_bytes) == Point.expected_bytes_length(is_compressed=True)