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-rw-r--r--bip-0340/reference.py78
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))