diff options
Diffstat (limited to 'pyecsca/ec/signature.py')
| -rw-r--r-- | pyecsca/ec/signature.py | 64 |
1 files changed, 35 insertions, 29 deletions
diff --git a/pyecsca/ec/signature.py b/pyecsca/ec/signature.py index dbfb30d..8c8630b 100644 --- a/pyecsca/ec/signature.py +++ b/pyecsca/ec/signature.py @@ -7,6 +7,7 @@ from public import public from .context import getcontext from .formula import AdditionFormula +from .group import AbelianGroup from .mod import Mod from .mult import ScalarMultiplier from .point import Point @@ -53,12 +54,13 @@ class SignatureResult(object): class Signature(object): """An EC based signature primitive. (ECDSA)""" mult: ScalarMultiplier + group: AbelianGroup add: Optional[AdditionFormula] pubkey: Optional[Point] privkey: Optional[int] hash_algo: Optional[Any] - def __init__(self, mult: ScalarMultiplier, add: Optional[AdditionFormula] = None, + def __init__(self, mult: ScalarMultiplier, group: AbelianGroup, add: Optional[AdditionFormula] = None, pubkey: Optional[Point] = None, privkey: Optional[int] = None, hash_algo: Optional[Any] = None): if pubkey is None and privkey is None: @@ -69,6 +71,7 @@ class Signature(object): else: add = mult.formulas["add"] self.mult = mult + self.group = group self.add = add self.pubkey = pubkey self.privkey = privkey @@ -86,18 +89,19 @@ class Signature(object): def _get_nonce(self, nonce: Optional[int]) -> Mod: if nonce is None: - return Mod(secrets.randbelow(self.mult.group.order), self.mult.group.order) + return Mod(secrets.randbelow(self.group.order), self.group.order) else: - return Mod(nonce, self.mult.group.order) + return Mod(nonce, self.group.order) def _do_sign(self, nonce: Mod, digest: bytes) -> SignatureResult: z = int.from_bytes(digest, byteorder="big") - if len(digest) * 8 > self.mult.group.order.bit_length(): - z >>= len(digest) * 8 - self.mult.group.order.bit_length() - point = self.mult.multiply(int(nonce), self.mult.group.generator) + if len(digest) * 8 > self.group.order.bit_length(): + z >>= len(digest) * 8 - self.group.order.bit_length() + self.mult.init(self.group, self.group.generator) + point = self.mult.multiply(int(nonce)) affine_point = point.to_affine() # TODO: add to context - r = Mod(int(affine_point.x), self.mult.group.order) - s = nonce.inverse() * (Mod(z, self.mult.group.order) + r * self.privkey) + r = Mod(int(affine_point.x), self.group.order) + s = nonce.inverse() * (Mod(z, self.group.order) + r * self.privkey) return SignatureResult(int(r), int(s), digest=digest, nonce=int(nonce), privkey=self.privkey) @@ -121,16 +125,18 @@ class Signature(object): def _do_verify(self, signature: SignatureResult, digest: bytes) -> bool: z = int.from_bytes(digest, byteorder="big") - if len(digest) * 8 > self.mult.group.order.bit_length(): - z >>= len(digest) * 8 - self.mult.group.order.bit_length() - c = Mod(signature.s, self.mult.group.order).inverse() - u1 = Mod(z, self.mult.group.order) * c - u2 = Mod(signature.r, self.mult.group.order) * c - p1 = self.mult.multiply(int(u1), self.mult.group.generator) - p2 = self.mult.multiply(int(u2), self.pubkey) - p = getcontext().execute(self.add, p1, p2, **self.mult.group.curve.parameters)[0] + if len(digest) * 8 > self.group.order.bit_length(): + z >>= len(digest) * 8 - self.group.order.bit_length() + c = Mod(signature.s, self.group.order).inverse() + u1 = Mod(z, self.group.order) * c + u2 = Mod(signature.r, self.group.order) * c + self.mult.init(self.group, self.group.generator) + p1 = self.mult.multiply(int(u1)) + self.mult.init(self.group, self.pubkey) + p2 = self.mult.multiply(int(u2)) + p = getcontext().execute(self.add, p1, p2, **self.group.curve.parameters)[0] affine = p.to_affine() # TODO: add to context - v = Mod(int(affine.x), self.mult.group.order) + v = Mod(int(affine.x), self.group.order) return signature.r == int(v) def verify_hash(self, signature: SignatureResult, digest: bytes) -> bool: @@ -154,51 +160,51 @@ class Signature(object): class ECDSA_NONE(Signature): """ECDSA with raw message input.""" - def __init__(self, mult: ScalarMultiplier, add: Optional[AdditionFormula] = None, + def __init__(self, mult: ScalarMultiplier, group: AbelianGroup, add: Optional[AdditionFormula] = None, pubkey: Optional[Point] = None, privkey: Optional[int] = None): - super().__init__(mult, add, pubkey, privkey) + super().__init__(mult, group, add, pubkey, privkey) @public class ECDSA_SHA1(Signature): """ECDSA with SHA1.""" - def __init__(self, mult: ScalarMultiplier, add: Optional[AdditionFormula] = None, + def __init__(self, mult: ScalarMultiplier, group: AbelianGroup, add: Optional[AdditionFormula] = None, pubkey: Optional[Point] = None, privkey: Optional[int] = None): - super().__init__(mult, add, pubkey, privkey, hashlib.sha1) + super().__init__(mult, group, add, pubkey, privkey, hashlib.sha1) @public class ECDSA_SHA224(Signature): """ECDSA with SHA224.""" - def __init__(self, mult: ScalarMultiplier, add: Optional[AdditionFormula] = None, + def __init__(self, mult: ScalarMultiplier, group: AbelianGroup, add: Optional[AdditionFormula] = None, pubkey: Optional[Point] = None, privkey: Optional[int] = None): - super().__init__(mult, add, pubkey, privkey, hashlib.sha224) + super().__init__(mult, group, add, pubkey, privkey, hashlib.sha224) @public class ECDSA_SHA256(Signature): """ECDSA with SHA256.""" - def __init__(self, mult: ScalarMultiplier, add: Optional[AdditionFormula] = None, + def __init__(self, mult: ScalarMultiplier, group: AbelianGroup, add: Optional[AdditionFormula] = None, pubkey: Optional[Point] = None, privkey: Optional[int] = None): - super().__init__(mult, add, pubkey, privkey, hashlib.sha256) + super().__init__(mult, group, add, pubkey, privkey, hashlib.sha256) @public class ECDSA_SHA384(Signature): """ECDSA with SHA384.""" - def __init__(self, mult: ScalarMultiplier, add: Optional[AdditionFormula] = None, + def __init__(self, mult: ScalarMultiplier, group: AbelianGroup, add: Optional[AdditionFormula] = None, pubkey: Optional[Point] = None, privkey: Optional[int] = None): - super().__init__(mult, add, pubkey, privkey, hashlib.sha384) + super().__init__(mult, group, add, pubkey, privkey, hashlib.sha384) @public class ECDSA_SHA512(Signature): """ECDSA with SHA512.""" - def __init__(self, mult: ScalarMultiplier, add: Optional[AdditionFormula] = None, + def __init__(self, mult: ScalarMultiplier, group: AbelianGroup, add: Optional[AdditionFormula] = None, pubkey: Optional[Point] = None, privkey: Optional[int] = None): - super().__init__(mult, add, pubkey, privkey, hashlib.sha512) + super().__init__(mult, group, add, pubkey, privkey, hashlib.sha512) |