Both server and client deterministically rotate the on-wire obfuscation mask
(SNI, HTTP Host/User-Agent/Server headers, UDP padding profile) at 05:00 Moscow
time (02:00 UTC) every day, derived from the CA fingerprint + UTC date — no
network coordination needed.
- aura-crypto::masks: MaskSet + 4 palettes (16 SNI, 10 UA, 5 Server, 4 padding
profiles); derive_mask_for_msk_date via HKDF-SHA256(salt="aura-mask-v1-salt",
ikm=ca_fp||"YYYY-MM-DD", info="aura-mask-v1"); ca_fingerprint with built-in
base64 PEM decode (no new deps).
- aura-cli::masks: MaskRotator (Arc<RwLock<MaskSet>>) + Hinnant's civil_from_days
for manual UTC date math; scheduler picks next 02:00 UTC strictly (avoids
busy-loop at boundary); spawned at startup in server::run/client::run.
- aura-transport: PADDING_PROFILES + next_bucket_for_profile (profile 0 byte-for-
byte equals legacy pad_to_https_size); TcpOpts gains user_agent/server_header;
UdpOpts gains padding_profile; MultiServer holds Arc<UdpServer>/Arc<TcpServer>
with set_udp_opts/set_tcp_opts so rotation propagates without restart.
- Backward-compatible: defaults preserve previous behavior; existing 97 tests
unchanged. 17 new tests (derive determinism + date variation, civil-from-days
known points incl. 1970-01-01/2000-02-29/2024->2025, next-rotation boundary,
msk_today offset, profile equivalence, base64 round-trip, full mask-driven
UDP loopback). Total: 114 passed, clippy/fmt clean. No new workspace deps.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
xah30
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