diff options
| -rw-r--r-- | bip-0340/reference.py | 78 |
1 files changed, 45 insertions, 33 deletions
diff --git a/bip-0340/reference.py b/bip-0340/reference.py index 6b1645c..f24963c 100644 --- a/bip-0340/reference.py +++ b/bip-0340/reference.py @@ -1,3 +1,4 @@ +from typing import Tuple, Optional, Any import hashlib import binascii @@ -17,22 +18,24 @@ n = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 # represented by the None keyword. G = (0x79BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798, 0x483ADA7726A3C4655DA4FBFC0E1108A8FD17B448A68554199C47D08FFB10D4B8) +Point = Tuple[int, int] + # This implementation can be sped up by storing the midstate after hashing # tag_hash instead of rehashing it all the time. -def tagged_hash(tag, msg): +def tagged_hash(tag: str, msg: bytes) -> bytes: tag_hash = hashlib.sha256(tag.encode()).digest() return hashlib.sha256(tag_hash + tag_hash + msg).digest() -def is_infinity(P): +def is_infinity(P: Optional[Point]) -> bool: return P is None -def x(P): +def x(P: Point) -> int: return P[0] -def y(P): +def y(P: Point) -> int: return P[1] -def point_add(P1, P2): +def point_add(P1: Optional[Point], P2: Optional[Point]) -> Optional[Point]: if P1 is None: return P2 if P2 is None: @@ -46,7 +49,7 @@ def point_add(P1, P2): x3 = (lam * lam - x(P1) - x(P2)) % p return (x3, (lam * (x(P1) - x3) - y(P1)) % p) -def point_mul(P, n): +def point_mul(P: Optional[Point], n: int) -> Optional[Point]: R = None for i in range(256): if (n >> i) & 1: @@ -54,16 +57,16 @@ def point_mul(P, n): P = point_add(P, P) return R -def bytes_from_int(x): +def bytes_from_int(x: int) -> bytes: return x.to_bytes(32, byteorder="big") -def bytes_from_point(P): +def bytes_from_point(P: Point) -> bytes: return bytes_from_int(x(P)) -def xor_bytes(b0, b1): +def xor_bytes(b0: bytes, b1: bytes) -> bytes: return bytes(x ^ y for (x, y) in zip(b0, b1)) -def lift_x_square_y(b): +def lift_x_square_y(b: bytes) -> Optional[Point]: x = int_from_bytes(b) if x >= p: return None @@ -73,36 +76,40 @@ def lift_x_square_y(b): return None return (x, y) -def lift_x_even_y(b): +def lift_x_even_y(b: bytes) -> Optional[Point]: P = lift_x_square_y(b) if P is None: return None else: return (x(P), y(P) if y(P) % 2 == 0 else p - y(P)) -def int_from_bytes(b): +def int_from_bytes(b: bytes) -> int: return int.from_bytes(b, byteorder="big") -def hash_sha256(b): +def hash_sha256(b: bytes) -> bytes: return hashlib.sha256(b).digest() -def is_square(x): - return pow(x, (p - 1) // 2, p) == 1 +def is_square(x: int) -> bool: + return int(pow(x, (p - 1) // 2, p)) == 1 -def has_square_y(P): - return (not is_infinity(P)) and is_square(y(P)) +def has_square_y(P: Optional[Point]) -> bool: + infinity = is_infinity(P) + if infinity: return False + assert P is not None + return is_square(y(P)) -def has_even_y(P): +def has_even_y(P: Point) -> bool: return y(P) % 2 == 0 -def pubkey_gen(seckey): +def pubkey_gen(seckey: bytes) -> bytes: d0 = int_from_bytes(seckey) if not (1 <= d0 <= n - 1): raise ValueError('The secret key must be an integer in the range 1..n-1.') P = point_mul(G, d0) + assert P is not None return bytes_from_point(P) -def schnorr_sign(msg, seckey, aux_rand): +def schnorr_sign(msg: bytes, seckey: bytes, aux_rand: bytes) -> bytes: if len(msg) != 32: raise ValueError('The message must be a 32-byte array.') d0 = int_from_bytes(seckey) @@ -111,12 +118,14 @@ def schnorr_sign(msg, seckey, aux_rand): if len(aux_rand) != 32: raise ValueError('aux_rand must be 32 bytes instead of %i.' % len(aux_rand)) P = point_mul(G, d0) + assert P is not None d = d0 if has_even_y(P) else n - d0 t = xor_bytes(bytes_from_int(d), tagged_hash("BIP340/aux", aux_rand)) k0 = int_from_bytes(tagged_hash("BIP340/nonce", t + bytes_from_point(P) + msg)) % n if k0 == 0: raise RuntimeError('Failure. This happens only with negligible probability.') R = point_mul(G, k0) + assert R is not None k = n - k0 if not has_square_y(R) else k0 e = int_from_bytes(tagged_hash("BIP340/challenge", bytes_from_point(R) + bytes_from_point(P) + msg)) % n sig = bytes_from_point(R) + bytes_from_int((k + e * d) % n) @@ -125,7 +134,7 @@ def schnorr_sign(msg, seckey, aux_rand): raise RuntimeError('The created signature does not pass verification.') return sig -def schnorr_verify(msg, pubkey, sig): +def schnorr_verify(msg: bytes, pubkey: bytes, sig: bytes) -> bool: if len(msg) != 32: raise ValueError('The message must be a 32-byte array.') if len(pubkey) != 32: @@ -153,26 +162,26 @@ import csv import os import sys -def test_vectors(): +def test_vectors() -> bool: all_passed = True with open(os.path.join(sys.path[0], 'test-vectors.csv'), newline='') as csvfile: reader = csv.reader(csvfile) reader.__next__() for row in reader: - (index, seckey, pubkey, aux_rand, msg, sig, result, comment) = row - pubkey = bytes.fromhex(pubkey) - msg = bytes.fromhex(msg) - sig = bytes.fromhex(sig) - result = result == 'TRUE' + (index, seckey_hex, pubkey_hex, aux_rand_hex, msg_hex, sig_hex, result_str, comment) = row + pubkey = bytes.fromhex(pubkey_hex) + msg = bytes.fromhex(msg_hex) + sig = bytes.fromhex(sig_hex) + result = result_str == 'TRUE' print('\nTest vector', ('#' + index).rjust(3, ' ') + ':') - if seckey != '': - seckey = bytes.fromhex(seckey) + if seckey_hex != '': + seckey = bytes.fromhex(seckey_hex) pubkey_actual = pubkey_gen(seckey) if pubkey != pubkey_actual: print(' * Failed key generation.') print(' Expected key:', pubkey.hex().upper()) print(' Actual key:', pubkey_actual.hex().upper()) - aux_rand = bytes.fromhex(aux_rand) + aux_rand = bytes.fromhex(aux_rand_hex) try: sig_actual = schnorr_sign(msg, seckey, aux_rand) if sig == sig_actual: @@ -207,7 +216,7 @@ def test_vectors(): # import inspect -def pretty(v): +def pretty(v: Any) -> Any: if isinstance(v, bytes): return '0x' + v.hex() if isinstance(v, int): @@ -216,9 +225,12 @@ def pretty(v): return tuple(map(pretty, v)) return v -def debug_print_vars(): +def debug_print_vars() -> None: if DEBUG: - frame = inspect.currentframe().f_back + current_frame = inspect.currentframe() + assert current_frame is not None + frame = current_frame.f_back + assert frame is not None print(' Variables in function ', frame.f_code.co_name, ' at line ', frame.f_lineno, ':', sep='') for var_name, var_val in frame.f_locals.items(): print(' ' + var_name.rjust(11, ' '), '==', pretty(var_val)) |