diff options
Diffstat (limited to 'bip-schnorr/reference.py')
-rw-r--r-- | bip-schnorr/reference.py | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/bip-schnorr/reference.py b/bip-schnorr/reference.py index e5d9557..7de37c2 100644 --- a/bip-schnorr/reference.py +++ b/bip-schnorr/reference.py @@ -11,6 +11,9 @@ def tagged_hash(tag, msg): tag_hash = hashlib.sha256(tag.encode()).digest() return hashlib.sha256(tag_hash + tag_hash + msg).digest() +def is_infinity(P): + return P is None + def x(P): return P[0] @@ -59,11 +62,11 @@ def int_from_bytes(b): def hash_sha256(b): return hashlib.sha256(b).digest() -def jacobi(x): - return pow(x, (p - 1) // 2, p) +def is_square(x): + return pow(x, (p - 1) // 2, p) == 1 -def is_quad(x): - return jacobi(x) == 1 +def has_square_y(P): + return not is_infinity(P) and is_square(y(P)) def pubkey_gen(seckey): x = int_from_bytes(seckey) @@ -79,12 +82,12 @@ def schnorr_sign(msg, seckey0): if not (1 <= seckey0 <= n - 1): raise ValueError('The secret key must be an integer in the range 1..n-1.') P = point_mul(G, seckey0) - seckey = seckey0 if is_quad(y(P)) else n - seckey0 + seckey = seckey0 if has_square_y(P) else n - seckey0 k0 = int_from_bytes(tagged_hash("BIPSchnorrDerive", bytes_from_int(seckey) + msg)) % n if k0 == 0: raise RuntimeError('Failure. This happens only with negligible probability.') R = point_mul(G, k0) - k = n - k0 if not is_quad(y(R)) else k0 + k = n - k0 if not has_square_y(R) else k0 e = int_from_bytes(tagged_hash("BIPSchnorr", bytes_from_point(R) + bytes_from_point(P) + msg)) % n return bytes_from_point(R) + bytes_from_int((k + e * seckey) % n) @@ -104,7 +107,7 @@ def schnorr_verify(msg, pubkey, sig): return False e = int_from_bytes(tagged_hash("BIPSchnorr", sig[0:32] + pubkey + msg)) % n R = point_add(point_mul(G, s), point_mul(P, n - e)) - if R is None or not is_quad(y(R)) or x(R) != r: + if R is None or not has_square_y(R) or x(R) != r: return False return True |