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EM4x70 Authentication support

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This commit is contained in:
Christian Molson 2020-12-12 09:59:30 -05:00
commit a6024a8622
7 changed files with 138 additions and 1 deletions
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63
armsrc/em4x70.c
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@ -360,6 +360,46 @@ static bool check_ack(void) {
return false;
}
static int authenticate(const uint8_t *rnd, const uint8_t *frnd, uint8_t *response) {
if (find_listen_window(true)) {
em4x70_send_nibble(EM4X70_COMMAND_AUTH, true);
// Send 56-bit Random number
for(int i=0;i<7;i++) {
em4x70_send_byte(rnd[i]);
}
// Send 7 x 0's (Diversity bits)
for(int i=0; i<7; i++) {
em4x70_send_bit(0);
}
// Send 28-bit f(RN)
// Send first 24 bits
for(int i=0; i < 3; i++) {
em4x70_send_byte(frnd[i]);
}
// Send last 4 bits (no parity)
em4x70_send_nibble((frnd[3] >> 4) & 0xf, false);
// Receive header, 20-bit g(RN), LIW
uint8_t grnd[EM4X70_MAX_RECEIVE_LENGTH] = {0};
int num = em4x70_receive(grnd);
if(num < 10) {
Dbprintf("Auth failed");
return PM3_ESOFT;
}
bits2bytes(grnd, 24, response);
return PM3_SUCCESS;
}
return PM3_ESOFT;
}
static int send_pin(const uint32_t pin) {
// sends pin code for unlocking
@ -387,7 +427,7 @@ static int send_pin(const uint32_t pin) {
// <w> Writes Lock Bits
WaitTicks(TICKS_PER_FC * EM4X70_T_TAG_WEE);
// <-- Receive header + ID
uint8_t tag_id[64];
uint8_t tag_id[EM4X70_MAX_RECEIVE_LENGTH];
int num = em4x70_receive(tag_id);
if(num < 32) {
Dbprintf("Invalid ID Received");
@ -731,4 +771,25 @@ void em4x70_unlock(em4x70_data_t *etd) {
reply_ng(CMD_LF_EM4X70_UNLOCK, status, tag.data, sizeof(tag.data));
}
void em4x70_auth(em4x70_data_t *etd) {
uint8_t status = 0;
uint8_t response[3] = {0};
command_parity = etd->parity;
init_tag();
EM4170_setup_read();
// Find the Tag
if (get_signalproperties() && find_EM4X70_Tag()) {
// Authenticate and get tag response
status = authenticate(etd->rnd, etd->frnd, response) == PM3_SUCCESS;
}
StopTicks();
lf_finalize();
reply_ng(CMD_LF_EM4X70_AUTH, status, response, sizeof(response));
}