[ADD] Inverse Key method

1200wd · Oct 31, 2023 · e37fa6f · e37fa6f
1 parent 20594e8
commit e37fa6f
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Showing 3 changed files with 17 additions and 4 deletions.
diff --git a/bitcoinlib/config/secp256k1.py b/bitcoinlib/config/secp256k1.py
@@ -23,12 +23,12 @@
 
 # Parameters secp256k1
 #  from http://www.secg.org/sec2-v2.pdf, par 2.4.1
-secp256k1_p = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F
-secp256k1_n = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141
+secp256k1_p = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F  # field size
+secp256k1_n = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141  # order
 secp256k1_b = 7
 secp256k1_a = 0
-secp256k1_Gx = 0x79BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798
-secp256k1_Gy = 0x483ADA7726A3C4655DA4FBFC0E1108A8FD17B448A68554199C47D08FFB10D4B8
+secp256k1_Gx = 0x79BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798 # generator point x
+secp256k1_Gy = 0x483ADA7726A3C4655DA4FBFC0E1108A8FD17B448A68554199C47D08FFB10D4B8 # generator point y
 
 # secp256k1_curve = ecdsa.ellipticcurve.CurveFp(secp256k1_p, secp256k1_a, secp256k1_b)
 # secp256k1_generator = ecdsa.ellipticcurve.Point(secp256k1_curve, secp256k1_Gx, secp256k1_Gy, secp256k1_n)
diff --git a/bitcoinlib/keys.py b/bitcoinlib/keys.py
@@ -977,6 +977,10 @@ def __mul__(self, other):
     def __rmul__(self, other):
         return self * other
 
+    def __neg__(self):
+        assert self.secret
+        return HDKey(secp256k1_n - self.secret)
+
     def __len__(self):
         return len(self.public_byte)
 

diff --git a/tests/test_keys.py b/tests/test_keys.py
@@ -65,6 +65,15 @@ def test_keys_proof_distributivity_of_scalar_operations(self):
         kc = HDKey()
         self.assertTrue(((ka - kb) * kc) == ((ka * kc) - (kb * kc)))
 
+    def test_keys_inverse(self):
+        secret = 95695802915573022935630358993164660366922511389187789518108651759801046161623
+        inv_x = 18153291153288219155018628681705413538294494009875615719062204619491226452658
+        inv_y = 67935514921393906349711087930011707333238709725906400058836382320969451605430
+        k = Key(secret)
+        k_inv = -k
+        self.assertEqual(k_inv.x, inv_x)
+        self.assertEqual(k_inv.y, inv_y)
+
     def test_dict_and_json_outputs(self):
         k = HDKey()
         k.address(script_type='p2wsh', encoding='bech32')