Replace MD5 hasher with SHA-256

tf_quant_finance/experimental/pricing_platform/framework/utils.py

@@ -18,6 +18,6 @@
 
 
 def hasher(obj):
-  """Returns non-cryptographic hash of a JSON-serializable object."""
-  h = hashlib.md5(json.dumps(obj).encode())
+  """Returns a stable SHA-256 hash of a JSON-serializable object."""
+  h = hashlib.sha256(json.dumps(obj).encode())
   return h.hexdigest()

tf_quant_finance/experimental/pricing_platform/framework/utils_test.py

@@ -0,0 +1,45 @@
+# Copyright 2020 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Tests for framework utility functions."""
+
+import hashlib
+import importlib.util
+import json
+import pathlib
+import unittest
+
+
+_UTILS_PATH = pathlib.Path(__file__).with_name("utils.py")
+_SPEC = importlib.util.spec_from_file_location("framework_utils", _UTILS_PATH)
+utils = importlib.util.module_from_spec(_SPEC)
+_SPEC.loader.exec_module(utils)
+
+
+class UtilsTest(unittest.TestCase):
+
+  def test_hasher_uses_sha256(self):
+    payload = {
+        "bank_holidays": ["2026-01-01", "2026-12-25"],
+        "business_day_convention": "MODIFIED_FOLLOWING",
+        "currency": "USD",
+    }
+
+    expected = hashlib.sha256(json.dumps(payload).encode()).hexdigest()
+
+    self.assertEqual(expected, utils.hasher(payload))
+    self.assertEqual(64, len(utils.hasher(payload)))
+
+
+if __name__ == "__main__":
+  unittest.main()