nx_tls13_record_test.nx

nx_tls13_record_test.nx -- internal-consistency KAT for the TLS 1.3 record-layer protection wrapper. We don't pin to RFC 8448 §3 wire bytes here because those depend on the full key schedule + traffic-secret derivation tied to specific handshake messages. Instead we verify: A. Round-trip: encrypt then decrypt restores plaintext + type B. Nonce-with-seq: encrypt(seq=0) != encrypt(seq=1) given same (key, iv, content) -- confirms IV XOR seq actually varies the keystream C. Tampered tag rejected (TAG_MISMATCH) D. Tampered header (wrong length in AAD) rejected E. Padding: encrypt with padding_len > 0, decrypt strips it F. All-zeros inner (no type byte) rejected (EMPTY_INNER) G. Nonce construction byte-exact for known (iv, seq) pair expect_exit: 0 license_tier: ORIGINAL