GitHub/dsd-fme
1
0
Fork 0
mirror of https://github.com/lwvmobile/dsd-fme.git synced 2026-11-13 01:07:24 -05:00
Code Issues Packages Projects Releases Wiki Activity

MBE: Add NXDN AES Decryption support (untested) for SDRTrunk .mbe files; #298

Browse Source
This commit is contained in:
lwvmobile
2026-07-10 16:39:16 -04:00
parent 6fd7176659
commit 69d31151dd
1 changed files with 25 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
src/dsd_file.c
View File

@@ -1582,10 +1582,6 @@ void read_sdrtrunk_json_format (dsd_opts * opts, dsd_state * state)
{
//Hytera BP
}
else if (state->R != 0)
{
//NXDN Scrambler
}
}
if (strncmp ("to", str_buffer, 2) == 0)
@@ -1862,9 +1858,10 @@ void read_sdrtrunk_json_format (dsd_opts * opts, dsd_state * state)
//WIP: Add handling for NXDN DES and AES256
//NOTE: This hinges on where SDRTrunk places the IV for the call,
//ideally needs to be after the SACCH4 voice frames
//NOTE: This will NOT WORK on Type-D with its 22-bit IV
//I doubt anybody will ever test that theory out here either
else if (protocol == 3 && alg_id == 2 && state->R != 0)
{
//double check discards (seems same as in dsd_mbe)
des_multi_keystream_output(iv_hex, state->R, ks_bytes, 1, 32);
unpack_byte_array_into_bit_array(ks_bytes+8, ks, 256-8);
@@ -1876,10 +1873,30 @@ void read_sdrtrunk_json_format (dsd_opts * opts, dsd_state * state)
}
else if (protocol == 3 && alg_id == 3 && state->aes_key_loaded[0] == 1)
{
//TODO: All of This
// ambe2_counter = 0;
// ks_idx = 0;
uint8_t aes_key[32];
memset (aes_key, 0, sizeof(aes_key));
//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;
}
//Generate 128-bit IV for AES
LFSR128npdu(state); //npdu variant uses payload_mi here, and loads to aes_ivR
aes_ofb_keystream_output (state->aes_ivR, aes_key, ks_bytes, 2, 16);
unpack_byte_array_into_bit_array(ks_bytes+16, ks, 256-16);
ambe2_counter = 0;
ks_idx = 0;
ks_available = 1;
}
//Pull request: https://github.com/DSheirer/sdrtrunk/pull/2273