From a6301c5af08d39121c1e1e7dc9ad1b9e9fe45942 Mon Sep 17 00:00:00 2001 From: Tim Ruffing Date: Wed, 4 Mar 2020 21:21:36 +0100 Subject: Optionally print intermediate values in reference code and make reference code and pseudocode more consistent with each other --- bip-0340/reference.py | 68 +++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 53 insertions(+), 15 deletions(-) (limited to 'bip-0340') diff --git a/bip-0340/reference.py b/bip-0340/reference.py index 79f9578..d6106fd 100644 --- a/bip-0340/reference.py +++ b/bip-0340/reference.py @@ -1,6 +1,15 @@ import hashlib import binascii +# Set DEBUG to True to get a detailed debug output including +# intermediate values during key generation, signing, and +# verification. This is implemented via calls to the +# debug_print_vars() function. +# +# If you want to print values on an individual basis, use +# the pretty() function, e.g., print(pretty(foo)). +DEBUG = False + p = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F n = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 @@ -62,7 +71,7 @@ def lift_x_square_y(b): y = pow(y_sq, (p + 1) // 4, p) if pow(y, 2, p) != y_sq: return None - return [x, y] + return (x, y) def lift_x_even_y(b): P = lift_x_square_y(b) @@ -87,32 +96,37 @@ def has_even_y(P): return y(P) % 2 == 0 def pubkey_gen(seckey): - x = int_from_bytes(seckey) - if not (1 <= x <= n - 1): + d0 = int_from_bytes(seckey) + if not (1 <= d0 <= n - 1): + debug_print_vars() raise ValueError('The secret key must be an integer in the range 1..n-1.') - P = point_mul(G, x) + P = point_mul(G, d0) return bytes_from_point(P) -def schnorr_sign(msg, seckey0, aux_rand): +def schnorr_sign(msg, seckey, aux_rand): if len(msg) != 32: + debug_print_vars() raise ValueError('The message must be a 32-byte array.') - seckey0 = int_from_bytes(seckey0) - if not (1 <= seckey0 <= n - 1): + 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.') if len(aux_rand) != 32: raise ValueError('aux_rand must be 32 bytes instead of %i.' % len(aux_rand)) - P = point_mul(G, seckey0) - seckey = seckey0 if has_even_y(P) else n - seckey0 - t = xor_bytes(bytes_from_int(seckey), tagged_hash("BIP340/aux", aux_rand)) + P = point_mul(G, d0) + 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: + debug_print_vars() raise RuntimeError('Failure. This happens only with negligible probability.') R = point_mul(G, k0) 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 * seckey) % n) + sig = bytes_from_point(R) + bytes_from_int((k + e * d) % n) if not schnorr_verify(msg, bytes_from_point(P), sig): + debug_print_vars() raise RuntimeError('The signature does not pass verification.') + debug_print_vars() return sig def schnorr_verify(msg, pubkey, sig): @@ -123,26 +137,29 @@ def schnorr_verify(msg, pubkey, sig): if len(sig) != 64: raise ValueError('The signature must be a 64-byte array.') P = lift_x_even_y(pubkey) - if (P is None): - return False r = int_from_bytes(sig[0:32]) s = int_from_bytes(sig[32:64]) - if (r >= p or s >= n): + if (P is None) or (r >= p) or (s >= n): + debug_print_vars() return False e = int_from_bytes(tagged_hash("BIP340/challenge", sig[0:32] + pubkey + msg)) % n R = point_add(point_mul(G, s), point_mul(P, n - e)) if R is None or not has_square_y(R) or x(R) != r: + debug_print_vars() return False + debug_print_vars() return True # # The following code is only used to verify the test vectors. # import csv +import os +import sys def test_vectors(): all_passed = True - with open('test-vectors.csv', newline='') as csvfile: + with open(os.path.join(sys.path[0], 'test-vectors.csv'), newline='') as csvfile: reader = csv.reader(csvfile) reader.__next__() for row in reader: @@ -185,5 +202,26 @@ def test_vectors(): print('Some test vectors failed.') return all_passed +# +# The following code is only used for debugging +# +import inspect + +def pretty(v): + if isinstance(v, bytes): + return '0x' + v.hex() + if isinstance(v, int): + return pretty(bytes_from_int(v)) + if isinstance(v, tuple): + return tuple(map(pretty, v)) + return v + +def debug_print_vars(): + if DEBUG: + frame = inspect.currentframe().f_back + 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)) + if __name__ == '__main__': test_vectors() -- cgit v1.2.3