Rename BIPs

1 files changed, 169 insertions, 0 deletions

diff --git a/bip-0340/reference.py b/bip-0340/reference.py
new file mode 100644
index 0000000..f2a944f
--- /dev/null
+++ b/bip-0340/reference.py
@@ -0,0 +1,169 @@
+import hashlib
+import binascii
+
+p = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F
+n = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141
+
+# Points are tuples of X and Y coordinates and the point at infinity is
+# represented by the None keyword.
+G = (0x79BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798, 0x483ADA7726A3C4655DA4FBFC0E1108A8FD17B448A68554199C47D08FFB10D4B8)
+
+# 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):
+    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]
+
+def y(P):
+    return P[1]
+
+def point_add(P1, P2):
+    if (P1 is None):
+        return P2
+    if (P2 is None):
+        return P1
+    if (x(P1) == x(P2) and y(P1) != y(P2)):
+        return None
+    if (P1 == P2):
+        lam = (3 * x(P1) * x(P1) * pow(2 * y(P1), p - 2, p)) % p
+    else:
+        lam = ((y(P2) - y(P1)) * pow(x(P2) - x(P1), p - 2, p)) % p
+    x3 = (lam * lam - x(P1) - x(P2)) % p
+    return (x3, (lam * (x(P1) - x3) - y(P1)) % p)
+
+def point_mul(P, n):
+    R = None
+    for i in range(256):
+        if ((n >> i) & 1):
+            R = point_add(R, P)
+        P = point_add(P, P)
+    return R
+
+def bytes_from_int(x):
+    return x.to_bytes(32, byteorder="big")
+
+def bytes_from_point(P):
+    return bytes_from_int(x(P))
+
+def point_from_bytes(b):
+    x = int_from_bytes(b)
+    if x >= p:
+        return None
+    y_sq = (pow(x, 3, p) + 7) % p
+    y = pow(y_sq, (p + 1) // 4, p)
+    if pow(y, 2, p) != y_sq:
+        return None
+    return [x, y]
+
+def int_from_bytes(b):
+    return int.from_bytes(b, byteorder="big")
+
+def hash_sha256(b):
+    return hashlib.sha256(b).digest()
+
+def is_square(x):
+    return pow(x, (p - 1) // 2, p) == 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)
+    if not (1 <= x <= n - 1):
+        raise ValueError('The secret key must be an integer in the range 1..n-1.')
+    P = point_mul(G, x)
+    return bytes_from_point(P)
+
+def schnorr_sign(msg, seckey0):
+    if len(msg) != 32:
+        raise ValueError('The message must be a 32-byte array.')
+    seckey0 = int_from_bytes(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 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 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)
+
+def schnorr_verify(msg, pubkey, sig):
+    if len(msg) != 32:
+        raise ValueError('The message must be a 32-byte array.')
+    if len(pubkey) != 32:
+        raise ValueError('The public key must be a 32-byte array.')
+    if len(sig) != 64:
+        raise ValueError('The signature must be a 64-byte array.')
+    P = point_from_bytes(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):
+        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 has_square_y(R) or x(R) != r:
+        return False
+    return True
+
+#
+# The following code is only used to verify the test vectors.
+#
+import csv
+
+def test_vectors():
+    all_passed = True
+    with open('test-vectors.csv', newline='') as csvfile:
+        reader = csv.reader(csvfile)
+        reader.__next__()
+        for row in reader:
+            (index, seckey, pubkey, msg, sig, result, comment) = row
+            pubkey = bytes.fromhex(pubkey)
+            msg = bytes.fromhex(msg)
+            sig = bytes.fromhex(sig)
+            result = result == 'TRUE'
+            print('\nTest vector #%-3i: ' % int(index))
+            if seckey != '':
+                seckey = bytes.fromhex(seckey)
+                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())
+                sig_actual = schnorr_sign(msg, seckey)
+                if sig == sig_actual:
+                    print(' * Passed signing test.')
+                else:
+                    print(' * Failed signing test.')
+                    print('   Expected signature:', sig.hex().upper())
+                    print('     Actual signature:', sig_actual.hex().upper())
+                    all_passed = False
+            result_actual = schnorr_verify(msg, pubkey, sig)
+            if result == result_actual:
+                print(' * Passed verification test.')
+            else:
+                print(' * Failed verification test.')
+                print('   Expected verification result:', result)
+                print('     Actual verification result:', result_actual)
+                if comment:
+                    print('   Comment:', comment)
+                all_passed = False
+    print()
+    if all_passed:
+        print('All test vectors passed.')
+    else:
+        print('Some test vectors failed.')
+    return all_passed
+
+if __name__ == '__main__':
+    test_vectors()