- test/gen_chacha_kat.py emits KAT from RFC 8439 section 2.4.2 mapped to the impl's 64+64 counter/nonce layout; expected bytes cross-checked against pycryptodome (independent impl) and the official vector: 10f1e7e4d13b5915... byte-exact
- verdict: the 'intermittent chacha20 KAT FAIL' referenced in FUCK comments was a phantom — that test was never merged into this tree; the implementation itself matches RFC byte-for-byte
- selftest now runs KAT + page-MAC determinism checks at selftest=2; full SELFTEST PASS in QEMU (.build_tmp/qemu_serial_u5kat.log)
