'Backend method for verifing the the captured credentials
:param self: Handshakeverify object
:param list_data: list data from phishinghttp
:type self: Handshakeverify
:type list_data: list
:return \'success\' if the password correct else return \'fail\'
:rtype: string'

@extensions.register_backend_funcs
def psk_verify(self, *list_data):

    while (len(self._eapols) > 3):
        ap_bssid = self._data.target_ap_bssid
        msg1 = self._eapols[0]
        msg2 = self._eapols[1]
        msg3 = self._eapols[2]
        msg4 = self._eapols[3]
        if ((msg1.addr2 == ap_bssid) and (msg3.addr2 == ap_bssid) and (msg2.addr1 == ap_bssid) and (msg4.addr1 == ap_bssid)):
            self._is_done = self._verify_creds(list_data[0])
            self._is_captured = True
            pop_pkt = self._eapols.popleft()
            self._store_eapols.append(pop_pkt)
        if (self._is_done == DONE):
            return 'success'
        else:
            pop_pkt = self._eapols.popleft()
            self._store_eapols.append(pop_pkt)
    self._eapols = deque((self._store_eapols + list(self._eapols)))
    self._store_eapols = []
    if self._is_captured:
        return 'fail'
    return 'not-captured'
