A non-SI device (120) is arranged for wireless communication (130) and cooperates with an SI device (110) having access to a subscriber identity. The non-SI device has a transceiver (121) to communicate in a local network and a processor (122) to establish an association with the SI. A non-SI public key is provided to the SI device via a first communication channel. A verification code is shared with the SI device via a second communication channel. The channels are different and include an out-of-band channel (140). Proof of possession of a non-SI private key is provided to the SI device via the first or the second communication channel. From the SI device, security data is received that is related to the SI and is computed using the non-SI public key. The security data reliably enables the non-SI device to access the core network via the local network and a gateway between the local network and the core network.