Python cleanup v2

.flake8

@@ -1,5 +1,6 @@
 [flake8]
-ignore = E203, E266, E501, W503, F403, F401
+exclude = .??*, venv
+ignore = E203, E266, E501
 max-line-length = 88
 max-complexity = 18
-select = B,C,E,F,W,T4,B9
+select = B,C,E,F,W,T4,B9

README.md

@@ -71,17 +71,17 @@ Bluetooth devices or backend services.
 
 You'll need to install the project. For example as follows:
 
-```
+```bash
 python3 -m venv venv
 source venv/bin/activate
-pip3 install -e "."
+pip3 install -e .
 ```
 
 ## Running the example
 
 After installing the project you can run the examples:
 
-```
+```bash
 examples/run_lowcost.py
 examples/run_unlinkable.py
 ```
@@ -90,7 +90,7 @@ examples/run_unlinkable.py
 
 After installing the project you can obtain test vectors by running:
 
-```
+```bash
 utils/testvectors_lowcost.py
 utils/testvectors_unlinkable.py
 ```
@@ -105,7 +105,7 @@ venv/bin/ativate`) to ensure that the paths are picked up correctly.
 
 Please install the proper pre-commit-hooks so that the files stay formatted:
 
-```
+```bash
 pip install pre-commit
 pre-commit install
 ```

dp3t/protocols/lowcost.py

@@ -77,6 +77,18 @@ def batch_start_from_time(time):
     return (int(time.timestamp()) // SECONDS_PER_BATCH) * SECONDS_PER_BATCH
 
 
+def secure_shuffle(items):
+    """Perform a cryptographically secure shuffling of the given items
+
+    Args:
+        items (obj:list): A list of items to be shuffled
+
+    Returns:
+        Nothing. Items are shuffled in place
+    """
+    random.shuffle(items, secrets.SystemRandom().random)
+
+
 #########################################
 ### BASIC CRYPTOGRAPHIC FUNCTIONALITY ###
 #########################################
@@ -130,8 +142,7 @@ def generate_ephids_for_day(current_day_key, shuffle=True):
 
     # Shuffle the resulting ephids
     if shuffle:
-        # WARNING: replace with a secure shuffle
-        random.shuffle(ephids)
+        secure_shuffle(ephids)
 
     return ephids
 
@@ -310,7 +321,7 @@ def add_observation(self, ephid, time):
         self.observations[batch_start].append(ephid)
 
         # Shuffle observations to hide receive order
-        random.shuffle(self.observations[batch_start])
+        secure_shuffle(self.observations[batch_start])
 
     def get_tracing_information(
         self,
@@ -451,4 +462,4 @@ def housekeeping_after_batch(self, batch):
             self.observations[day_time].extend(observations)
 
             # Reshuffle to make sure we do not store ordering data
-            random.shuffle(self.observations[day_time])
+            secure_shuffle(self.observations[day_time])

examples/run_lowcost.py

@@ -125,6 +125,7 @@ def main():
         print("  * CORRECT: Alice's phone concludes she is at risk")
     else:
         print("  * ERROR: Alice's phone does not conclude she is at risk")
+        raise RuntimeError("Example code failed!")
 
     print("\n[Alice] Runs housekeeping to update her observation store")
     alice.housekeeping_after_batch(batch)

examples/run_unlinkable.py

@@ -127,6 +127,7 @@ def main():
         print("  * CORRECT: Alice's phone concludes she is at risk")
     else:
         print("  * ERROR: Alice's phone does not conclude she is at risk")
+        raise RuntimeError("Example code failed!")
 
 
 if __name__ == "__main__":

setup.py

@@ -18,7 +18,7 @@
         "License :: OSI Approved :: Apache Software License"
         "Operating System :: OS Independent",
     ],
-    install_requires=["pycryptodomex", "scalable-cuckoo-filter"],
-    test_requires=["pytest"],
     python_requires=">=3.6",
+    install_requires=["pycryptodomex", "scalable-cuckoo-filter"],
+    extras_require={"dev": ["black", "flake8", "pre-commit"], "test": ["pytest"]},
 )

tests/test_examples.py

@@ -0,0 +1,27 @@
+__copyright__ = """
+    Copyright 2020 EPFL
+
+    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
+
+        http://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.
+"""
+__license__ = "Apache 2.0"
+
+from pathlib import Path
+import pytest
+import subprocess
+
+example_scripts = (Path(__file__).parent.parent / "examples").glob("*.py")
+
+
+@pytest.mark.parametrize("script", example_scripts)
+def test_example_script(script):
+    subprocess.run([script], check=True)

utils/testvectors_lowcost.py

@@ -19,8 +19,6 @@
 """
 __license__ = "Apache 2.0"
 
-from datetime import datetime, timezone
-
 from dp3t.protocols.lowcost import next_day_key, generate_ephids_for_day
 
 KEY0 = bytes.fromhex("0000000000000000000000000000000000000000000000000000000000000000")

utils/testvectors_unlinkable.py

@@ -19,7 +19,7 @@
 """
 __license__ = "Apache 2.0"
 
-from binascii import hexlify, unhexlify
+from binascii import unhexlify
 from datetime import datetime, timezone
 
 from dp3t.protocols.unlinkable import (