*     ...
 *
 * NOTES
 *     ...
 *
 */
static cackey_ret cackey_login(struct cackey_slot *slot, unsigned char *pin, unsigned long pin_len, int *tries_remaining_p) {
	struct cackey_pcsc_identity *pcsc_identities;
	unsigned char cac_pin[8] = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};
	unsigned long num_certs;
	uint16_t response_code;
	int tries_remaining;
	int send_ret;
	int key_reference = 0x00;

	/* Indicate that we do not know about how many tries are remaining */
	if (tries_remaining_p) {
		*tries_remaining_p = -1;
	}

	/* Apparently, CAC PINs are *EXACTLY* 8 bytes long -- pad with 0xFF if too short */
	if (pin_len >= 8) {
		memcpy(cac_pin, pin, 8);
	} else {
		memcpy(cac_pin, pin, pin_len);
	}

	/* PIV authentication uses a "key_reference" of 0x80 */
	pcsc_identities = cackey_read_certs(slot, NULL, &num_certs);
	if (num_certs > 0 && pcsc_identities != NULL) {
		switch (pcsc_identities[0].id_type) {
			case CACKEY_ID_TYPE_PIV:
				CACKEY_DEBUG_PRINTF("We recently had a PIV card, so we will attempt to authenticate using the PIV Application key reference");

				key_reference = 0x80;
				break;
			default:
				break;
		}
	}

	/* Issue PIN Verify */
	send_ret = cackey_send_apdu(slot, GSCIS_CLASS_ISO7816, GSCIS_INSTR_VERIFY, 0x00, key_reference, sizeof(cac_pin), cac_pin, 0x00, &response_code, NULL, NULL);






	if (send_ret != CACKEY_PCSC_S_OK) {
		if ((response_code & 0x63C0) == 0x63C0) {
			tries_remaining = (response_code & 0xF);

			CACKEY_DEBUG_PRINTF("PIN Verification failed, %i tries remaining", tries_remaining);