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MBE: Add DMRA Late Entry IV and Forced AES Alg Decryption support (w/ known key) for SDRTrunk .mbe files; #298

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lwvmobile
2026-07-20 11:31:31 -04:00
parent 69d31151dd
commit 272f17bfa3
1 changed files with 38 additions and 1 deletions
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39
src/dsd_file.c
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@@ -1038,7 +1038,7 @@ uint16_t ambe2_str_to_decode(dsd_opts * opts, dsd_state * state, char * ambe_str
//run LFSR evaluate stored codewords for matching IV or replace if not match or not set
if (ambe2_counter == 17)
{
if (state->payload_mi != 0)
if (state->forced_alg_id == 0x21 && state->payload_mi != 0)
{
fprintf (stderr, "\n");
LFSR(state);
@@ -1561,6 +1561,43 @@ void read_sdrtrunk_json_format (dsd_opts * opts, dsd_state * state)
}
else if ((alg_id == 0x24 || alg_id == 0x25) && state->payload_mi != 0)
{
uint8_t ks_bytes[375];
memset(ks_bytes, 0, sizeof(ks_bytes));
uint8_t aes_key[32];
memset(aes_key, 0, sizeof(aes_key));
uint8_t empty[32];
memset(empty, 0, sizeof(empty));
//Load key from A1 - A4
for (int i = 0; i < 8; i++)
{
aes_key[i+0] = (state->A1[0] >> (56-(i*8))) & 0xFF;
aes_key[i+8] = (state->A2[0] >> (56-(i*8))) & 0xFF;
aes_key[i+16] = (state->A3[0] >> (56-(i*8))) & 0xFF;
aes_key[i+24] = (state->A4[0] >> (56-(i*8))) & 0xFF;
}
//check to see if a key is actually loaded
if (memcmp (aes_key, empty, sizeof(aes_key)) != 0)
{
if (alg_id == 0x24) //128, or 256
aes_ofb_keystream_output(state->aes_iv, aes_key, ks_bytes, 0, 16); //16*16=256
else aes_ofb_keystream_output(state->aes_iv, aes_key, ks_bytes, 2, 16); //16*16=256
unpack_byte_array_into_bit_array(ks_bytes+16, ks, 256-16); //unpack starting after discards
ks_available = 1;
}
}
}
//TODO: This
else if (state->forced_alg_id == 1) //Basic Privacy