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[TAS-110] verify_tesla_key-> implement retrieval tesla key

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This commit is contained in:
cesaaargm 2023-12-07 05:34:52 +01:00
parent 55e624e9f8
commit 1356a3e87b
1 changed files with 16 additions and 1 deletions
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17
src/core/libs/osnma_msg_receiver.cc
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@ -512,6 +512,7 @@ void osnma_msg_receiver::read_mack_header()
void osnma_msg_receiver::read_mack_body()
{
uint8_t lt_bits = 0;
const auto it = OSNMA_TABLE_11.find(d_osnma_data.d_dsm_kroot_message.ts);
if (it != OSNMA_TABLE_11.cend())
@ -534,7 +535,7 @@ void osnma_msg_receiver::read_mack_body()
}
uint16_t nt = std::floor((480.0 - float(lk_bits)) / (float(lt_bits) + 16.0)); // C: compute number of tags
d_osnma_data.d_mack_message.tag_and_info = std::vector<MACK_tag_and_info>(nt - 1);
for (uint16_t k = 0; k < (nt - 1); k++)
for (uint16_t k = 0; k < (nt - 1); k++) // C: retrieve Tag&Info
{
uint64_t tag = 0;
uint8_t PRN_d = 0;
@ -679,6 +680,20 @@ void osnma_msg_receiver::read_mack_body()
d_osnma_data.d_mack_message.tag_and_info[k].tag_info.ADKD = ADKD;
d_osnma_data.d_mack_message.tag_and_info[k].tag_info.cop = cop;
}
// TODO - [TAS-110]
// retrieve TESLA key: index i is [479-MH(l_t)-(nt-1)*(16+l_t), i+l_k]
// compute I (GST_SFi,GST_Kroot)
// perform recursive hash calls until base case: i = 10...1
// retrieve tesla key
uint8_t start_index_bytes = ( 480 - (lt_bits + 16) - (nt - 1) * ( lt_bits + 16 ) - 1 ) / 8; // includes -1 to start at [i-1]
uint8_t last_index_bytes = ( start_index_bytes * 8 + lk_bits ) / 8;
uint8_t key_index_bytes = 0;
for (uint8_t i = start_index_bytes; i < last_index_bytes ; i++, key_index_bytes++)
{
d_osnma_data.d_mack_message.key[key_index_bytes] = d_mack_message[i];
}
}