Error when using a lock after pairing

[tomerazran]

Hello,

I'm trying to setup a new lock on a raspberry pi using PN532.
I'm pairing a lock on apple home application and it works. The lock is added to home.
A new homekey.json file is created:

{
  "reader_private_key": "0000000000000000000000000000000000000000000000000000000000000000",
  "reader_identifier": "0000000000000000",
  "issuers": {
    "8b2ec053ab96cd85": {
      "public_key": "edf3e592519307edc3758b0568c717bcff20b4af92e38036f73a8f346ea5e286",
      "endpoints": {}
    }
  }
}

When trying to use the lock, I'm getting an error:

[2024-12-04 12:45:42,864] [    INFO] hap_protocol      :82   ('192.168.36.45', 53320): Connection made to NFC Lock
[2024-12-04 12:45:44,185] [    INFO] accessory_driver  :697  Paired with b'6AB288D8-F7C8-4768-8DDD-A42093E0AA4C' with permissions b'\x01'.
[2024-12-04 12:45:44,516] [    INFO] hap_protocol      :82   ('192.168.36.45', 53321): Connection made to NFC Lock
[2024-12-04 12:45:44,886] [    INFO] service           :107  Adding issuer Issuer(public_key=edf3e592519307edc3758b0568c717bcff20b4af92e38036f73a8f346ea5e286, endpoints=[]) based on paired clients
[2024-12-04 12:45:44,906] [    INFO] accessory         :150  get_hardware_finish
[2024-12-04 12:45:44,918] [    INFO] service           :286  get_hardware_finish=AQTj4+MA
[2024-12-04 12:45:44,924] [    INFO] accessory         :127  get_lock_current_state
[2024-12-04 12:45:44,926] [    INFO] accessory         :131  get_lock_target_state
[2024-12-04 12:45:44,929] [    INFO] accessory         :141  get_lock_version
[2024-12-04 12:45:44,931] [    INFO] accessory         :170  get_configuration_state
[2024-12-04 12:45:44,933] [    INFO] service           :341  get_configuration_state
[2024-12-04 12:45:44,934] [    INFO] accessory         :160  get_nfc_access_control_point
[2024-12-04 12:45:44,936] [    INFO] service           :299  get_nfc_access_control_point
[2024-12-04 12:45:44,939] [    INFO] accessory         :155  get_nfc_access_supported_configuration
[2024-12-04 12:45:44,948] [    INFO] service           :295  TODO get_nfc_access_supported_configuration=AQEQAgEQ
[2024-12-04 12:46:06,264] [    INFO] hap_protocol      :82   ('192.168.36.45', 53323): Connection made to NFC Lock
[2024-12-04 12:46:06,330] [    INFO] accessory         :150  get_hardware_finish
[2024-12-04 12:46:06,335] [    INFO] service           :286  get_hardware_finish=AQTj4+MA
[2024-12-04 12:46:06,340] [    INFO] accessory         :127  get_lock_current_state
[2024-12-04 12:46:06,347] [    INFO] accessory         :131  get_lock_target_state
[2024-12-04 12:46:06,353] [    INFO] accessory         :141  get_lock_version
[2024-12-04 12:46:06,362] [    INFO] accessory         :170  get_configuration_state
[2024-12-04 12:46:06,369] [    INFO] service           :341  get_configuration_state
[2024-12-04 12:46:06,374] [    INFO] accessory         :160  get_nfc_access_control_point
[2024-12-04 12:46:06,377] [    INFO] service           :299  get_nfc_access_control_point
[2024-12-04 12:46:06,382] [    INFO] accessory         :155  get_nfc_access_supported_configuration
[2024-12-04 12:46:06,391] [    INFO] service           :295  TODO get_nfc_access_supported_configuration=AQEQAgEQ
[2024-12-04 12:46:50,119] [    INFO] service           :139  Got NFC tag Type4ATag MIU=253 FWT=0.038664
[2024-12-04 12:46:50,124] [    INFO] homekey           :533  SELECT CMD = ISO7816Command(cla=0x00; ins=0xa4; p1=0x04; p2=0x00; lc=0x07(7); data=a0000008580101; le=0x00)
[2024-12-04 12:46:50,162] [    INFO] homekey           :539  SELECT RES = ISO7816Response(sw1=0x90; sw2=0x00; data=5c0402000100(6))
[2024-12-04 12:46:50,168] [    INFO] homekey           :712  reader_identifier=5a5864ea45ab5f560000000000000000
[2024-12-04 12:46:50,172] [    INFO] homekey           :725  Choosing preferred version b'\x02\x00'
[2024-12-04 12:46:50,176] [   ERROR] threads           :17   Unhandled exception in runner homekey. Continuing in 5 seconds
Traceback (most recent call last):
  File "/home/dorone/homekey/apple-home-key-reader/util/threads.py", line 15, in function_
    target(*args, **kwargs)
  File "/home/dorone/homekey/apple-home-key-reader/service.py", line 190, in run
    self._read_homekey()
  File "/home/dorone/homekey/apple-home-key-reader/service.py", line 143, in _read_homekey
    result_flow, new_issuers_state, endpoint = read_homekey(
                                               ^^^^^^^^^^^^^
  File "/home/dorone/homekey/apple-home-key-reader/homekey.py", line 733, in read_homekey
    reader_private_key = ec.derive_private_key(
                         ^^^^^^^^^^^^^^^^^^^^^^
  File "/home/dorone/homekey/venv/lib/python3.11/site-packages/cryptography/hazmat/primitives/asymmetric/ec.py", line 350, in derive_private_key
    raise ValueError("private_value must be a positive integer.")
ValueError: private_value must be a positive integer.

Can you please advise?

[kormax]

Hi,

The reason is, that your primary Home device didn't seem to have had a chance to provision the encryption key into the reader (the one which is all zeroes in your config), hence why it fails the authentication.

In my set up it happens pretty quickly (in under a couple of seconds after adding the lock), so one thing I could suggest would be to "interact" with that virtual lock from your primary Home controller, which could cause it to try to update the keys.

There doesn't seem to be any problems apart from that, you can even see that one of your devices provisioned itself into the lock, so overall communication and command handling works as needed.

[tomerazran]

Hi,

Thanks for the quick response.
I actually tried to setup when the primary home device is not on the same network as the raspberry pi.
I will try to have them both on the same network and let you know if it works.

[toyssan1]

I have the same issue, but I think it might be something to do with the phone. It works with an iphone 12, but not with an iphone 15.

[tomerazran]

When both devices on same network - the issue is solved.