README.md

Crypto Library Tests

This folder contains test data and infrastructure for the OpenTitan cryptographic library. Tests come from a variety of sources, including:

• Our own hard-coded tests and regression tests
• wycheproof
• Random tests
• Coming soon: FIPS tests!

The primary way of running crypto tests is to use the custom autogen_cryptotest_... Bazel rules, which create build targets specialized to different test sets.

Note: New crypto tests should be written using the cryptotest framework.

Setup

Each algorithm has a C test file (ending in _functest.c) which reads test data from a header file (ending in _testvectors.h) and runs a set of tests on each test vector. By default, the header file contains a small set of hard-coded test vectors. If all you want to do is sanity-check, then simply run ninja and run the _functest target (e.g. sw_lib_crypto_rsa_3072_verify_functest) on your desired platform.

However, if you want to run a set of test vectors from an external source, a custom set of tests, or random tests, you'll need to populate the *_testvectors.h header file with the tests you want to run. There is a Python script for this for each algorithm, ending in set_testvectors.py (e.g. rsa_3072_verify_set_testvectors.py). It reads an HJSON file containing your test vectors, and writes a C header file containing the data in the format expected from `*_testvectors.h". For test vectors from an external source, you may need an extra script to parse the test vectors into the shared HJSON format.

For example, here's the setup for just one algorithm, RSA-3072 verify:

tests/
  rsa_3072_verify_functest.c                 # Main test file
  rsa_3072_verify_set_testvectors.py         # Generates header from HJSON
  rsa_3072_verify_gen_random_testvectors.py  # Generates random test vectors
  testvectors/
    rsa_3072_verify_hardcoded.hjson          # Limited set of hard-coded tests
    wycheproof/
      rsa_3072_verify_parse_testvectors.py   # Parses raw test data to HJSON
    ...

Adding New Hardcoded Tests

To add a new hardcoded test for some algorithm, simply edit the testvectors/{algorithm}_hardcoded.hjson file. Bazel rules based on the hardcoded tests will automatically pick up the changes.

Adding New External Tests

If an external test data dependency such as wycheproof has been updated, there should be no action required here unless file names have changed. The build rules are designed to directly read external data from sw/vendor at build time.

To add an entirely new test set, create a new folder under testvectors/ and write a script that reads the external data and translates tests into the standardized HJSON format for that algorithm. Pass the script and input data to an autogen_cryptotest_hjson_external build target.

Example Direct Usage

To run the tests locally and manually (as opposed to via Bazel), see the following examples.

Set up RSA-3072 test to run hardcoded test vectors:

$ ./rsa_3072_verify_set_testvectors.py testvectors/rsa_3072_verify_hardcoded.hjson

After this step, you can run ninja to re-build and then run the sw_lib_crypto_rsa_3072_verify_functest target to run the tests. The same applies to all other examples here.

Set up RSA-3072 test to run 20 random test vectors:

$ ./rsa_3072_verify_gen_random_testvectors.py 20 testvectors/rsa_3072_verify_random.hjson
$ ./rsa_3072_verify_set_testvectors.py testvectors/rsa_3072_verify_random.hjson rsa_3072_verify_testvectors.h

Set up RSA-3072 test to run a custom set of test vectors:

$ vim testvectors/custom_testvecs.hjson # write test vectors in HJSON format
$ ./rsa_3072_verify_set_testvectors.py testvectors/custom_testvecs.hjson

Set up RSA-3072 test to run all wycheproof test vectors:

$ testvectors/wycheproof/rsa_3072_verify_parse_testvectors.py\
  $REPO_TOP/sw/vendor/wycheproof/testvectors/rsa_signature_3072_sha256_test.json\
  testvectors/rsa_3072_verify_wycheproof.hjson
$ ./rsa_3072_verify_set_testvectors.py testvectors/rsa_3072_verify_wycheproof.hjson rsa_3072_verify_testvectors.h