AttributeError in NISTStatisticalTests.nist_statistical_tests() when running avalanche test

[antonyef]

I'm trying to run NIST statistical tests on Speck cipher using CLAASP, but getting an AttributeError when calling nist_statistical_tests() method with 'avalanche' test type.

[peacker]

Hi @antonyef, thanks for creating the issue!
Unfortunately, the NIST Statistical Tests module has often caused trouble, as it uses the original NIST C implementation, which generates several files from which we extract the output. We are considering reimplementing the statistical tests in Python to better integrate them into the CLAASP framework.
You can check the branch https://github.com/Crypto-TII/claasp/tree/feature/python-nist-sts-implementation, where the tests are now in Python, and your issue should be fixed.

Below are more details on the fix:

Fixed

The AttributeError has been resolved in commit 490eeb8 on branch feature/python-nist-sts-implementation.

Root Cause:
The dataset_type attribute was only set inside specific test type blocks (if test_type == 'avalanche', etc.). When the code path didn't enter these blocks or if dataset generation failed early, the attribute wouldn't exist when accessed later.

Solution:
Added defensive hasattr(self, 'dataset_type') checks in two locations:

1. Line ~251: When logging dataset generation time
2. Line ~708: When setting the data_type field in the report dictionary

Fallback values are now used when dataset_type is not set:

• 'Compute dataset' for execution time logging
• 'unknown' for the data type in the report

Testing:
All NIST statistical tests pass: 9 passed, 1 skipped (too long)

Files Changed:

• claasp/cipher_modules/statistical_tests/nist_statistical_tests.py

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