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M17 - AES IV Replay Warning;

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lwvmobile 2024-03-05 12:44:19 -05:00
parent ec7fbeeb22
commit a2113fcdcc
1 changed files with 5 additions and 0 deletions
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5
src/m17.c
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@ -172,6 +172,11 @@ void M17decodeLSF(dsd_state * state)
state->m17_enc = lsf_et;
state->m17_enc_st = lsf_es;
//compare incoming META/IV value on AES, if timestamp 32-bits are not a match (or at least 24 bit, warn user of potential replay/compromise)
uint32_t tsn = (time(NULL) & 0xFFFFFFFF) >> 8; //evaluate 24 bits (within a 255 second window)
uint32_t tsi = (uint32_t)ConvertBitIntoBytes(&state->m17_lsf[112], 24);
if (lsf_et == 2 && tsn != tsi) fprintf (stderr, " \n WARNING! NONCE/IV REPLAY!");
//pack meta bits into 14 bytes
for (i = 0; i < 14; i++)
state->m17_meta[i] = (uint8_t)ConvertBitIntoBytes(&state->m17_lsf[(i*8)+112], 8);