bip-0352: do not require the optional expected argument

bip-0352/reference.py

@@ -137,7 +137,8 @@ def create_outputs(input_priv_keys: List[Tuple[Scalar, bool]], outpoints: List[C
     if a_sum == 0:
         # Input privkeys sum is zero -> fail
         return []
-    assert Scalar.from_bytes_checked(bytes.fromhex(expected.get("input_private_key_sum"))) == a_sum, "a_sum did not match expected input_private_key_sum"
+    if expected is not None:
+        assert Scalar.from_bytes_checked(bytes.fromhex(expected.get("input_private_key_sum"))) == a_sum, "a_sum did not match expected input_private_key_sum"
     input_hash_scalar = Scalar.from_bytes_checked(get_input_hash(outpoints, a_sum * G))
     silent_payment_groups: Dict[GE, List[GE]] = {}
     for recipient in recipients:
@@ -159,14 +160,15 @@ def create_outputs(input_priv_keys: List[Tuple[Scalar, bool]], outpoints: List[C
     outputs = []
     for B_scan, B_m_values in silent_payment_groups.items():
         ecdh_shared_secret = input_hash_scalar * a_sum * B_scan
-        expected_shared_secrets = expected.get("shared_secrets", {})
-        # Find the recipient address that corresponds to this B_scan and get its index
-        for recipient_idx, recipient in enumerate(recipients):
-            recipient_B_scan = GE.from_bytes_compressed(bytes.fromhex(recipient["scan_pub_key"]))
-            if recipient_B_scan == B_scan:
-                expected_shared_secret_hex = expected_shared_secrets[recipient_idx]
-                assert ecdh_shared_secret.to_bytes_compressed().hex() == expected_shared_secret_hex, f"ecdh_shared_secret did not match expected, recipient {recipient_idx} ({recipient['address']}): expected={expected_shared_secret_hex}"
-                break
+        if expected is not None:
+            expected_shared_secrets = expected.get("shared_secrets", {})
+            # Find the recipient address that corresponds to this B_scan and get its index
+            for recipient_idx, recipient in enumerate(recipients):
+                recipient_B_scan = GE.from_bytes_compressed(bytes.fromhex(recipient["scan_pub_key"]))
+                if recipient_B_scan == B_scan:
+                    expected_shared_secret_hex = expected_shared_secrets[recipient_idx]
+                    assert ecdh_shared_secret.to_bytes_compressed().hex() == expected_shared_secret_hex, f"ecdh_shared_secret did not match expected, recipient {recipient_idx} ({recipient['address']}): expected={expected_shared_secret_hex}"
+                    break
         k = 0
         for B_m in B_m_values:
             t_k = Scalar.from_bytes_checked(tagged_hash("BIP0352/SharedSecret", ecdh_shared_secret.to_bytes_compressed() + ser_uint32(k)))
@@ -180,9 +182,10 @@ def create_outputs(input_priv_keys: List[Tuple[Scalar, bool]], outpoints: List[C
 def scanning(b_scan: Scalar, B_spend: GE, A_sum: GE, input_hash: bytes, outputs_to_check: List[bytes], labels: Dict[str, str] = None, expected: Dict[str, Any] = None) -> List[Dict[str, str]]:
     input_hash_scalar = Scalar.from_bytes_checked(input_hash)
     computed_tweak_point = input_hash_scalar * A_sum
-    assert computed_tweak_point.to_bytes_compressed().hex() == expected.get("tweak"), "tweak did not match expected"
     ecdh_shared_secret = input_hash_scalar * b_scan * A_sum
-    assert ecdh_shared_secret.to_bytes_compressed().hex() == expected.get("shared_secret"), "ecdh_shared_secret did not match expected shared_secret"
+    if expected is not None:
+        assert computed_tweak_point.to_bytes_compressed().hex() == expected.get("tweak"), "tweak did not match expected"
+        assert ecdh_shared_secret.to_bytes_compressed().hex() == expected.get("shared_secret"), "ecdh_shared_secret did not match expected shared_secret"
     k = 0
     wallet = []
     while True: