//! Kia V6 protocol decoder //! //! Ported from protopirate's kia_v6.c //! //! Protocol characteristics: //! - Manchester encoding: 200/400µs timing //! - 144 bits total (split into 3 parts) //! - Long preamble of 600+ pairs //! - AES-128 encryption //! - Decode-only (no encoder) use super::{ProtocolDecoder, ProtocolTiming, DecodedSignal}; use crate::radio::demodulator::LevelDuration; use crate::duration_diff; const TE_SHORT: u32 = 200; const TE_LONG: u32 = 400; const TE_DELTA: u32 = 100; const MIN_COUNT_BIT: usize = 144; const PREAMBLE_COUNT: u16 = 601; const XOR_MASK_LOW: u32 = 0x84AF25FB; const XOR_MASK_HIGH: u32 = 0x638766AB; /// AES S-box const AES_SBOX: [u8; 256] = [ 0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, 0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, 0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, 0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16, ]; /// AES inverse S-box const AES_SBOX_INV: [u8; 256] = [ 0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb, 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb, 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e, 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25, 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92, 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84, 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06, 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b, 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73, 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e, 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b, 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4, 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f, 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef, 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61, 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d, ]; const AES_RCON: [u8; 10] = [0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36]; /// Manchester states #[derive(Debug, Clone, Copy, PartialEq)] enum ManchesterState { Mid0, Mid1, Start0, Start1, } /// Decoder states #[derive(Debug, Clone, Copy, PartialEq)] enum DecoderStep { Reset, WaitFirstHigh, WaitLongHigh, Data, } /// Kia V6 protocol decoder pub struct KiaV6Decoder { step: DecoderStep, te_last: u32, header_count: u16, manchester_state: ManchesterState, data_part1_low: u32, data_part1_high: u32, stored_part1_low: u32, stored_part1_high: u32, stored_part2_low: u32, stored_part2_high: u32, data_part3: u16, bit_count: u8, } impl KiaV6Decoder { pub fn new() -> Self { Self { step: DecoderStep::Reset, te_last: 0, header_count: 0, manchester_state: ManchesterState::Mid1, data_part1_low: 0, data_part1_high: 0, stored_part1_low: 0, stored_part1_high: 0, stored_part2_low: 0, stored_part2_high: 0, data_part3: 0, bit_count: 0, } } /// Get keystore A (placeholder) fn get_keystore_a() -> u64 { 0x0000000000000000 } /// Get keystore B (placeholder) fn get_keystore_b() -> u64 { 0x0000000000000000 } /// CRC8 calculation fn crc8(data: &[u8], init: u8, polynomial: u8) -> u8 { let mut crc = init; for &byte in data { crc ^= byte; for _ in 0..8 { let b = crc << 1; if (crc & 0x80) != 0 { crc = b ^ polynomial; } else { crc = b; } } } crc } /// GF(2^8) multiply by 2 fn gf_mul2(x: u8) -> u8 { ((x >> 7).wrapping_mul(0x1b)) ^ (x << 1) } /// AES inverse SubBytes fn aes_subbytes_inv(state: &mut [u8; 16]) { for i in 0..16 { state[i] = AES_SBOX_INV[state[i] as usize]; } } /// AES inverse ShiftRows fn aes_shiftrows_inv(state: &mut [u8; 16]) { let temp = state[13]; state[13] = state[9]; state[9] = state[5]; state[5] = state[1]; state[1] = temp; let temp = state[2]; state[2] = state[10]; state[10] = temp; let temp = state[6]; state[6] = state[14]; state[14] = temp; let temp = state[3]; state[3] = state[7]; state[7] = state[11]; state[11] = state[15]; state[15] = temp; } /// AES inverse MixColumns fn aes_mixcolumns_inv(state: &mut [u8; 16]) { for i in 0..4 { let a = state[i * 4]; let b = state[i * 4 + 1]; let c = state[i * 4 + 2]; let d = state[i * 4 + 3]; let a2 = Self::gf_mul2(a); let a4 = Self::gf_mul2(a2); let a8 = Self::gf_mul2(a4); let b2 = Self::gf_mul2(b); let b4 = Self::gf_mul2(b2); let b8 = Self::gf_mul2(b4); let c2 = Self::gf_mul2(c); let c4 = Self::gf_mul2(c2); let c8 = Self::gf_mul2(c4); let d2 = Self::gf_mul2(d); let d4 = Self::gf_mul2(d2); let d8 = Self::gf_mul2(d4); state[i * 4] = (a8 ^ a4 ^ a2) ^ (b8 ^ b2 ^ b) ^ (c8 ^ c4 ^ c) ^ (d8 ^ d); state[i * 4 + 1] = (a8 ^ a) ^ (b8 ^ b4 ^ b2) ^ (c8 ^ c2 ^ c) ^ (d8 ^ d4 ^ d); state[i * 4 + 2] = (a8 ^ a4 ^ a) ^ (b8 ^ b) ^ (c8 ^ c4 ^ c2) ^ (d8 ^ d2 ^ d); state[i * 4 + 3] = (a8 ^ a2 ^ a) ^ (b8 ^ b4 ^ b) ^ (c8 ^ c) ^ (d8 ^ d4 ^ d2); } } /// AES AddRoundKey fn aes_addroundkey(state: &mut [u8; 16], round_key: &[u8]) { for i in 0..16 { state[i] ^= round_key[i]; } } /// AES key expansion fn aes_key_expansion(key: &[u8; 16]) -> [u8; 176] { let mut round_keys = [0u8; 176]; round_keys[..16].copy_from_slice(key); for i in 4..44 { let prev_word_idx = (i - 1) * 4; let mut b0 = round_keys[prev_word_idx]; let mut b1 = round_keys[prev_word_idx + 1]; let mut b2 = round_keys[prev_word_idx + 2]; let mut b3 = round_keys[prev_word_idx + 3]; if (i % 4) == 0 { let new_b0 = AES_SBOX[b1 as usize] ^ AES_RCON[(i / 4) - 1]; let new_b1 = AES_SBOX[b2 as usize]; let new_b2 = AES_SBOX[b3 as usize]; let new_b3 = AES_SBOX[b0 as usize]; b0 = new_b0; b1 = new_b1; b2 = new_b2; b3 = new_b3; } let back_word_idx = (i - 4) * 4; b0 ^= round_keys[back_word_idx]; b1 ^= round_keys[back_word_idx + 1]; b2 ^= round_keys[back_word_idx + 2]; b3 ^= round_keys[back_word_idx + 3]; let curr_word_idx = i * 4; round_keys[curr_word_idx] = b0; round_keys[curr_word_idx + 1] = b1; round_keys[curr_word_idx + 2] = b2; round_keys[curr_word_idx + 3] = b3; } round_keys } /// AES-128 decrypt fn aes128_decrypt(expanded_key: &[u8; 176], data: &mut [u8; 16]) { let mut state = *data; Self::aes_addroundkey(&mut state, &expanded_key[160..176]); for round in (1..10).rev() { Self::aes_shiftrows_inv(&mut state); Self::aes_subbytes_inv(&mut state); Self::aes_addroundkey(&mut state, &expanded_key[round * 16..(round + 1) * 16]); Self::aes_mixcolumns_inv(&mut state); } Self::aes_shiftrows_inv(&mut state); Self::aes_subbytes_inv(&mut state); Self::aes_addroundkey(&mut state, &expanded_key[0..16]); *data = state; } /// Get AES key from keystores fn get_aes_key() -> [u8; 16] { let keystore_a = Self::get_keystore_a(); let keystore_a_hi = ((keystore_a >> 32) & 0xFFFFFFFF) as u32; let keystore_a_lo = (keystore_a & 0xFFFFFFFF) as u32; let u_var15_a = keystore_a_lo ^ XOR_MASK_LOW; let u_var5_a = XOR_MASK_HIGH ^ keystore_a_hi; let val64_a = ((u_var5_a as u64) << 32) | (u_var15_a as u64); let keystore_b = Self::get_keystore_b(); let keystore_b_hi = ((keystore_b >> 32) & 0xFFFFFFFF) as u32; let keystore_b_lo = (keystore_b & 0xFFFFFFFF) as u32; let u_var15_b = keystore_b_lo ^ XOR_MASK_LOW; let u_var5_b = XOR_MASK_HIGH ^ keystore_b_hi; let val64_b = ((u_var5_b as u64) << 32) | (u_var15_b as u64); let mut aes_key = [0u8; 16]; for i in 0..8 { aes_key[i] = ((val64_a >> (56 - i * 8)) & 0xFF) as u8; } for i in 0..8 { aes_key[i + 8] = ((val64_b >> (56 - i * 8)) & 0xFF) as u8; } aes_key } /// Decrypt the stored data fn decrypt(&self) -> Option<(u32, u8, u32, bool)> { let mut encrypted_data = [0u8; 16]; encrypted_data[0] = ((self.stored_part1_high >> 8) & 0xFF) as u8; encrypted_data[1] = (self.stored_part1_high & 0xFF) as u8; encrypted_data[2] = ((self.stored_part1_low >> 24) & 0xFF) as u8; encrypted_data[3] = ((self.stored_part1_low >> 16) & 0xFF) as u8; encrypted_data[4] = ((self.stored_part1_low >> 8) & 0xFF) as u8; encrypted_data[5] = (self.stored_part1_low & 0xFF) as u8; encrypted_data[6] = ((self.stored_part2_high >> 24) & 0xFF) as u8; encrypted_data[7] = ((self.stored_part2_high >> 16) & 0xFF) as u8; encrypted_data[8] = ((self.stored_part2_high >> 8) & 0xFF) as u8; encrypted_data[9] = (self.stored_part2_high & 0xFF) as u8; encrypted_data[10] = ((self.stored_part2_low >> 24) & 0xFF) as u8; encrypted_data[11] = ((self.stored_part2_low >> 16) & 0xFF) as u8; encrypted_data[12] = ((self.stored_part2_low >> 8) & 0xFF) as u8; encrypted_data[13] = (self.stored_part2_low & 0xFF) as u8; encrypted_data[14] = ((self.data_part3 >> 8) & 0xFF) as u8; encrypted_data[15] = (self.data_part3 & 0xFF) as u8; let aes_key = Self::get_aes_key(); let expanded_key = Self::aes_key_expansion(&aes_key); Self::aes128_decrypt(&expanded_key, &mut encrypted_data); let decrypted = &encrypted_data; let calculated_crc = Self::crc8(&decrypted[..15], 0xFF, 0x07); let stored_crc = decrypted[15]; let crc_valid = (calculated_crc ^ stored_crc) < 2; // Serial: bytes 4-6 as 24-bit big-endian let serial = ((decrypted[4] as u32) << 16) | ((decrypted[5] as u32) << 8) | (decrypted[6] as u32); let button = decrypted[7]; let counter = ((decrypted[8] as u32) << 24) | ((decrypted[9] as u32) << 16) | ((decrypted[10] as u32) << 8) | (decrypted[11] as u32); Some((serial, button, counter, crc_valid)) } /// Manchester state machine fn manchester_advance(&mut self, is_short: bool, is_high: bool) -> Option { let event = match (is_short, is_high) { (true, true) => 0, // Short High (true, false) => 2, // Short Low (false, true) => 6, // Long High (false, false) => 4, // Long Low }; let (new_state, output) = match (self.manchester_state, event) { (ManchesterState::Mid0, 2) | (ManchesterState::Mid1, 2) => (ManchesterState::Start0, None), (ManchesterState::Mid0, 0) | (ManchesterState::Mid1, 0) => (ManchesterState::Start1, None), (ManchesterState::Start1, 2) => (ManchesterState::Mid1, Some(true)), (ManchesterState::Start1, 4) => (ManchesterState::Start0, Some(true)), (ManchesterState::Start0, 0) => (ManchesterState::Mid0, Some(false)), (ManchesterState::Start0, 6) => (ManchesterState::Start1, Some(false)), _ => (ManchesterState::Mid1, None), }; self.manchester_state = new_state; output } /// Add initial sync bits fn add_sync_bits(&mut self) { // Add 1, 1, 0, 1 as initial bits for bit in [true, true, false, true] { let carry = self.data_part1_low >> 31; self.data_part1_low = (self.data_part1_low << 1) | (bit as u32); self.data_part1_high = (self.data_part1_high << 1) | carry; self.bit_count += 1; } } } impl ProtocolDecoder for KiaV6Decoder { fn name(&self) -> &'static str { "Kia V6" } fn timing(&self) -> ProtocolTiming { ProtocolTiming { te_short: TE_SHORT, te_long: TE_LONG, te_delta: TE_DELTA, min_count_bit: MIN_COUNT_BIT, } } fn supported_frequencies(&self) -> &[u32] { &[433_920_000] } fn reset(&mut self) { self.step = DecoderStep::Reset; self.te_last = 0; self.header_count = 0; self.manchester_state = ManchesterState::Mid1; self.data_part1_low = 0; self.data_part1_high = 0; self.stored_part1_low = 0; self.stored_part1_high = 0; self.stored_part2_low = 0; self.stored_part2_high = 0; self.data_part3 = 0; self.bit_count = 0; } fn feed(&mut self, level: bool, duration: u32) -> Option { let is_short = duration_diff!(duration, TE_SHORT) < TE_DELTA; let is_long = duration_diff!(duration, TE_LONG) < TE_DELTA; match self.step { DecoderStep::Reset => { if level && is_short { self.step = DecoderStep::WaitFirstHigh; self.te_last = duration; self.header_count = 0; self.manchester_state = ManchesterState::Mid1; } } DecoderStep::WaitFirstHigh => { if level { return None; } let diff_short = duration_diff!(duration, TE_SHORT); let diff_long = duration_diff!(duration, TE_LONG); if diff_long < TE_DELTA && diff_long < diff_short { if self.header_count >= PREAMBLE_COUNT { self.header_count = 0; self.te_last = duration; self.step = DecoderStep::WaitLongHigh; return None; } } if diff_short >= TE_DELTA && diff_long >= TE_DELTA { self.step = DecoderStep::Reset; return None; } if duration_diff!(self.te_last, TE_SHORT) < TE_DELTA { self.te_last = duration; self.header_count += 1; } else { self.step = DecoderStep::Reset; } } DecoderStep::WaitLongHigh => { if !level { self.step = DecoderStep::Reset; return None; } let diff_long = duration_diff!(duration, TE_LONG); let diff_short = duration_diff!(duration, TE_SHORT); if diff_long >= TE_DELTA && diff_short >= TE_DELTA { self.step = DecoderStep::Reset; return None; } if duration_diff!(self.te_last, TE_LONG) >= TE_DELTA { self.step = DecoderStep::Reset; return None; } self.data_part1_low = 0; self.data_part1_high = 0; self.bit_count = 0; self.add_sync_bits(); self.step = DecoderStep::Data; } DecoderStep::Data => { if !is_short && !is_long { self.step = DecoderStep::Reset; return None; } if let Some(bit) = self.manchester_advance(is_short, level) { let carry = self.data_part1_low >> 31; self.data_part1_low = (self.data_part1_low << 1) | (bit as u32); self.data_part1_high = (self.data_part1_high << 1) | carry; self.bit_count += 1; if self.bit_count == 64 { self.stored_part1_low = !self.data_part1_low; self.stored_part1_high = !self.data_part1_high; self.data_part1_low = 0; self.data_part1_high = 0; } else if self.bit_count == 128 { self.stored_part2_low = !self.data_part1_low; self.stored_part2_high = !self.data_part1_high; self.data_part1_low = 0; self.data_part1_high = 0; } } self.te_last = duration; if self.bit_count as usize == MIN_COUNT_BIT { self.data_part3 = !(self.data_part1_low as u16); if let Some((serial, button, counter, crc_valid)) = self.decrypt() { let key_data = ((self.stored_part1_high as u64) << 32) | (self.stored_part1_low as u64); self.step = DecoderStep::Reset; return Some(DecodedSignal { serial: Some(serial), button: Some(button), counter: Some((counter & 0xFFFF) as u16), // V6 has 32-bit counter but we only store 16 crc_valid, data: key_data, data_count_bit: MIN_COUNT_BIT, encoder_capable: false, }); } self.step = DecoderStep::Reset; } } } None } fn supports_encoding(&self) -> bool { false // V6 is decode-only } fn encode(&self, _decoded: &DecodedSignal, _button: u8) -> Option> { None } }