                 }
             }
             else if (dormitory == 13)
-                nfc_handler->success = nfc.mifareclassic_AuthenticateBlock (nfc_handler->uid, nfc_handler->uidLength, nfc_handler->currentblock, nfc_handler->keyNumber, nfc_handler->KeyA_D4);
+                nfc_handler->success = nfc.mifareclassic_AuthenticateBlock (nfc_handler->uid, nfc_handler->uidLength, nfc_handler->currentblock, nfc_handler->keyNumber, nfc_handler->KeyA_Blank);
 
             Serial.println("");
             if (nfc_handler->success)

                        nfc_handler->success = nfc.mifareclassic_WriteDataBlock(nfc_handler->currentblock, nfc_handler->data);
                        if (nfc_handler->success)
                        {
                            Serial.print(F("Block "));Serial.print(nfc_handler->currentblock, DEC);
                            Serial.print(" ");
                            nfc.PrintHexChar(nfc_handler->data, 16);
                        }

                }
                else
                {
                    if (nfc_handler->currentblock >= 24 && nfc_handler->currentblock <= 26 && dormitory != 4)
                    {
                        if (dormitory == 3 || dormitory == 13)
                            nfc_handler->offset = nfc_handler->currentblock == 25 ? 6 : 7;
                        else
                            nfc_handler->offset = nfc_handler->currentblock == 25 ? 8 : 7;
                        if (dormitory == 13)
                        {
                            nfc_handler->success = nfc.mifareclassic_WriteDataBlock(nfc_handler->currentblock, nfc_handler->data);
                        }
                        nfc.mifareclassic_ReadDataBlock(nfc_handler->currentblock, nfc_handler->data);
                        nfc_handler->data[nfc_handler->offset - 1] = nfc_handler->balance[0];
                        nfc_handler->data[nfc_handler->offset] = nfc_handler->balance[1];
                        nfc_handler->success = nfc.mifareclassic_WriteDataBlock(nfc_handler->currentblock, nfc_handler->data);
                        if (nfc_handler->success)
                        {
                            Serial.print(F("new B "));Serial.print(nfc_handler->currentblock, DEC);
                            Serial.print(" ");
                            nfc.PrintHexChar(nfc_handler->data, 16);
                        }
