// Authenticates just one arbitrarily sized chunk of data
void HMACOnce(const unsigned char* key, const uint8_t klen,
const unsigned char* data, int len) {
HMACInit(key, klen);
while (len>=0) {
HMACBlock(data, len>SHA1_BLOCKSIZE?SHA1_BLOCKSIZE:len);
len -= SHA1_BLOCKSIZE;
data += SHA1_BLOCKSIZE;
}
HMACDone();
}
void JIG_Task (void) {
static int bytes_out = 0, bytes_in = 0;
Endpoint_SelectEndpoint(2);
if (Endpoint_IsReadWriteAllowed()) {
Endpoint_Read_Stream_LE (&jig_challenge_res[bytes_out], 8, NO_STREAM_CALLBACK) ;
Endpoint_ClearOUT();
bytes_out += 8;
if (bytes_out >= 64) {
//prepare the response (by guess?)
jig_challenge_res[1]--;
jig_challenge_res[3]++;
jig_challenge_res[6]++;
HMACBlock(&jig_challenge_res[CHALLENGE_INDEX],20);
USB_USBTask(); //just in case
HMACDone();
jig_challenge_res[7] = jig_id[0];
jig_challenge_res[8] = jig_id[1];
int i;
for( i = 0; i < 20; i++)
jig_challenge_res[9+i] = hmacdigest[i];
state = p5_challenged;
expire = 50; // was 90
}
}
Endpoint_SelectEndpoint(1);
if (Endpoint_IsReadWriteAllowed() && state == p5_challenged && expire == 0) {
if ( bytes_in < 64) {
Endpoint_Write_PStream_LE(&jig_challenge_res[bytes_in], 8, NO_STREAM_CALLBACK);
Endpoint_ClearIN();
bytes_in += 8;
if ( bytes_in >= 64) {
state = p5_responded;
expire = 50;
}
}
}
}
