KaraZajac
754af4134a
Brings KAT to 32 protocol decoders. Ported from the ProtoPirate reference and the D4C1-Labs/Flipper-ARF firmware: ProtoPirate (8): Kia V7, Ford V1, Ford V2, Ford V3, Chrysler V0, Honda Static, Honda V1, Land Rover V0. Flipper-ARF (6): Toyota, Land Rover RKE, Mazda Siemens, BMW CAS4, Porsche Cayenne, PSA2. Each decoder is gated (CRC / checksum / fixed markers / frame structure) so it cannot false-match existing protocols; every previously-decoding IMPORTS capture decodes unchanged. Real-capture decodes added for Ford V3 (LDV T80), Honda Static (Honda), Toyota (Camry NRZ variant), and PSA2 (Groupe PSA, serial 0x99EB25); the rest are validated by encode/decode round-trip and synthetic-frame tests. Also fixes a debug-only underflow panic in keeloq_common::keeloq_decrypt (15 - r underflowed; now wrapping_sub to match the reference's unsigned wrap; release behavior unchanged). Adds per-protocol docs, updates the README protocol table, capture metadata (encoding / RF / encryption), make-suggestion mapping, and CHANGELOG. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01JEfaKqzB3T4qsrybwfEi73
69 lines
3.2 KiB
Markdown
69 lines
3.2 KiB
Markdown
---
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layout: default
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---
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# Ford V1 Protocol
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**Rust module:** `src/protocols/ford_v1.rs`
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**Reference:** `REFERENCES/ProtoPirate/protocols/ford_v1.c`
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## Overview
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Ford V1 uses Manchester encoding at 65/130 µs. 136 bits / 17 bytes: key1 (bytes 0–6, 56 bits) + key2
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(bytes 7–14, 64 bits) + CRC16 (bytes 15–16). Preamble ≥50 long pulses, then a short-pulse sync window
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(`sync_event_count > 2`) replays buffered Manchester events and enters the 17-byte data collection. This
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is a ROLLING-code protocol.
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Crypto: a proprietary parity-based descrambling cipher operating on the 9-byte air block `raw[6..15]`,
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plus CRC16/CCITT (poly `0x1021`, init `0x0000`) over `raw[3..15]`. Emission is gated on CRC16 validity
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(with a 17-byte bit-inverted fallback) so it never false-matches. A strict branch
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(`decoded[3]==raw[5] && decoded[4]==raw[6]`) yields plaintext serial/button/counter; otherwise it is
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classified as encrypted/rolling (device id only). The Manchester transition table is the Flipper
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differential-Manchester table (same as Ford V0/V2).
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## Timing
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| Parameter | Value | Notes |
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|-------------|--------|------------------------------|
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| Short | 65 µs | ±39 µs (te_delta) |
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| Long | 130 µs | ±39 µs (preamble uses ±40) |
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| Min bits | 136 | 17 bytes |
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| Preamble | ≥50 long pulses | |
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## Frame Layout (136 bits / 17 bytes)
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- **bytes 0–6:** key1 (56 bits, big-endian) → `DecodedSignal.data`
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- **bytes 6–14:** air block (9 bytes) — descrambled to plaintext
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- **bytes 15–16:** CRC16/CCITT over bytes 3–14
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Plaintext fields (when the strict branch matches): serial = `plain[1..3] + plain[0]`, button = `plain[5]>>4`
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(Sync=0, Lock=1, Unlock=2, Trunk=4, Panic=8), counter = `((plain[5] & 0x0F) << 16) | plain[6..7]`. The
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`extra` word stashes the CRC16, the strict flag, and `plain[4]` so the encoder can rebuild the full frame.
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## RF
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- **Encoding:** Manchester (Flipper differential table)
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- **RF modulation:** FM
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- **Encryption:** proprietary parity descramble cipher + CRC16/CCITT gate; rolling code
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- **Frequencies:** 315 MHz, 433.92 MHz
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## Decoder Steps
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1. **Reset** — a long LOW pulse begins the preamble (count = 1).
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2. **Preamble** — count long pulses; after ≥50, a short pulse enters Sync.
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3. **Sync** — buffer short/long events; once `sync_event_count > 2`, replay the buffered events into Manchester and enter Data.
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4. **Data** — Manchester-decode and pack 17 bytes; at the 17th byte run `process_data` (CRC16 gate + descramble + field extraction) and emit on a valid CRC.
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## Encoder
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Supported (6 bursts). Faithful re-encode is only possible when the original frame's plaintext was
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recovered (strict branch); the encoder rebuilds the plaintext from fields + the stashed `plain[4]`,
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re-derives the air block + CRC16, and emits 6 bursts of a 400-pair long preamble + sync + 136 Manchester
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bits, with a per-burst `pkt[4]` override.
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## Validation
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Verified by an encode→decode round-trip / synthetic-frame check (no local capture available). Unit tests
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cover a CRC16/XMODEM known vector, the descramble round trip, the strict-branch decode, and a full
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encode→decode at the on-air-frame level.
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