we were copying private into ciphertext object accidentally

Author: serengil

lightphe/__init__.py

@@ -5,6 +5,7 @@
 import multiprocessing
 from contextlib import closing
 import traceback
+import copy
 
 # 3rd party dependencies
 from tqdm import tqdm
@@ -178,9 +179,14 @@ def encrypt(
                 value=plaintext, modulo=self.cs.plaintext_modulo
             )
         )
+
+        public_keys = self.cs.keys.copy()
+        if public_keys.get("private_key") is not None:
+            del public_keys["private_key"]
+
         return Ciphertext(
             algorithm_name=self.algorithm_name,
-            keys=self.cs.keys,
+            keys=public_keys,
             value=ciphertext,
             form=self.form,
             curve=self.curve,
@@ -254,9 +260,13 @@ def __encrypt_tensors(self, tensor: list, silent: bool = False) -> EncryptedTens
             toc = time.time()
             logger.debug(f"encryption took {toc - tic} seconds")
 
+            public_cs = copy.deepcopy(self.cs)
+            if public_cs.keys.get("private_key") is not None:
+                del public_cs.keys["private_key"]
+
             return EncryptedTensor(
                 fractions=encrypted_tensor,
-                cs=self.cs,
+                cs=public_cs,
                 precision=self.precision,
             )
 

tests/test_ciphertexts.py

@@ -0,0 +1,33 @@
+# 3rd party dependencies
+from lightphe import LightPHE
+
+# project dependencies
+from lightphe.commons.logger import Logger
+
+logger = Logger(module="tests/test_ciphertexts.py")
+
+
+def test_private_key_not_available_in_ciphertext():
+    onprem_cs = LightPHE(algorithm_name="Paillier")
+
+    m = 17
+
+    c = onprem_cs.encrypt(m)
+
+    assert c.cs.keys.get("private_key") is None
+    assert onprem_cs.cs.keys.get("private_key") is not None
+
+    logger.info("✅ Private key not available in ciphertext tests done")
+
+
+def test_private_key_not_available_in_encrypted_tensor():
+    onprem_cs = LightPHE(algorithm_name="Paillier")
+
+    t = [1.5, 2.4, 3.3, 4.2, 5.1]
+
+    c = onprem_cs.encrypt(t, silent=True)
+
+    assert c.cs.keys.get("private_key") is None
+    assert onprem_cs.cs.keys.get("private_key") is not None
+
+    logger.info("✅ Private key not available in encrypted tensor tests done")