a8c3454ba1 test: speedup bip324_cipher.py unit test (Sebastian Falbesoner)
Pull request description:
Executing the unit tests for the bip324_cipher.py module currently takes quite long (>60 seconds on my older notebook). Most time here is spent in empty plaintext/ciphertext encryption/decryption loops in `test_fschacha20poly1305aead`:
9eeee7caa3/test/functional/test_framework/crypto/bip324_cipher.py (L193-L194)9eeee7caa3/test/functional/test_framework/crypto/bip324_cipher.py (L198-L199)
Their sole purpose is increasing the FSChaCha20Poly1305 packet counter in order to trigger rekeying, i.e. the actual encryption/decryption is not relevant, as the result is thrown away. This commit speeds up the tests by supporting to pass "None" as plaintext/ciphertext, indicating to the routines that no actual encryption/decryption should be done.
The approach here is a bit hacky, a cleaner alternative would probably be to introduce a special `seek`/`skip_packets` method and not touch the encrypt/decrypt routines, but that seemed overkill to me only for speeding up a unit test. Open for suggestions.
master branch:
```
$ python3 -m unittest ./test/functional/test_framework/crypto/bip324_cipher.py
..
----------------------------------------------------------------------
Ran 2 tests in 64.658s
```
PR branch:
```
$ python3 -m unittest ./test/functional/test_framework/crypto/bip324_cipher.py
..
----------------------------------------------------------------------
Ran 2 tests in 0.822s
```
ACKs for top commit:
delta1:
Concept ACK a8c3454
epiccurious:
Tested ACK a8c3454ba1.
achow101:
ACK a8c3454ba1
marcofleon:
ACK a8c3454ba1. The comments at the top of `bip324_cipher.py` specify that this should only be used for testing, so I think this optimization makes sense in that context.
cbergqvist:
ACK a8c3454!
stratospher:
ACK a8c3454. I think it's worth it because of the significant speedup in the unit test.
Tree-SHA512: 737dd805a850be6e035aa3c6d9e2c5b5b5e89ddc564f84a045c37e0238fef6419912de7c902139b64914abdd647c649fe02a694f1a5e1741d7d4459c041caccc
be5399e785