diff options
| -rw-r--r-- | bip-schnorr/reference.py | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/bip-schnorr/reference.py b/bip-schnorr/reference.py index bd12212..016ce97 100644 --- a/bip-schnorr/reference.py +++ b/bip-schnorr/reference.py @@ -62,6 +62,9 @@ def hash_sha256(b): def jacobi(x): return pow(x, (p - 1) // 2, p) +def is_quad(x): + return jacobi(x) == 1 + def pubkey_gen(seckey): P = point_mul(G, seckey) return bytes_from_point(P) @@ -72,12 +75,12 @@ 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 (jacobi(y(P)) == 1) else n - seckey0 + seckey = seckey0 if is_quad(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 (jacobi(y(R)) != 1) else k0 + k = n - k0 if not is_quad(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) @@ -97,7 +100,7 @@ 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 jacobi(y(R)) != 1 or x(R) != r: + if R is None or not is_quad(y(R)) or x(R) != r: return False return True |