Authenticator not correct

Hello there,

I have a problem at the 14. SL verifies authenticator step of the initial authorisation process. Meanwhile the Nuki Smart Lock 3.0 device returns p_error_bad_authenticator error code.

I do generate private, public as well as I do retrieve public key of the Nuki Smart Lock itself. Based on the generated public key I do generate DH Key k on top of my private key and Nuki publickey. In further steps the shared secret gets generated. After concatinating the client public and Nuki public key with the received challenge, generated authenticator with the secret as well as concatinated message from the previous step, I do get an error back from the Nuki Smart Lock device that that the received authenticator does not match the own calculated authenticator.

My calculated values are following:

  • client private key: 080a548546159a8ca132b15bc62c22bcf73fdfd577811e1a254b09d5d4f2dc52
  • client public key: ef481c8bce1b9cb0cafa2b633cf4efbc596bb6c046d5520b59104044f76a1c24
  • nuki smart lock public key: fd7a64f0cc75729cce378c89696f0870e73af747eabfcfb7a46312b24a220272
  • derived dh key from cl private and nuki public: f72857409fd93805275a41c618da2f620f39cd595cc89db6bb22ac2afc7f0064
  • shared secret: ca5e76286c9e38eb388f006676482ced7ef4f934c2f965cb20466cbb3ba332e4
  • challenge received: a73cbab5460f413c0d805606d338257076466a1b53049b11cc62085aeba85607
  • calculated “r” - concatinated string: ef481c8bce1b9cb0cafa2b633cf4efbc596bb6c046d5520b59104044f76a1c24fd7a64f0cc75729cce378c89696f0870e73af747eabfcfb7a46312b24a220272a73cbab5460f413c0d805606d338257076466a1b53049b11cc62085aeba85607
  • authenticator: bf8bd9efb8552dca8826c6621a27c7c411b732b3e191b9fb19fa061d10323efe

Any help appreciated, thanks in advance