Non subscriber identity, non-SI, device arranged for wireless communication in a local network according to a local communication protocol, - the local communication protocol defining protocol messages and wireless transceiving across a limited area, the non-SI device not comprising an SI and being arranged for cooperating with an SI device having access to the SI, - the SI comprising subscriber identity data of a subscriber to a provider for accessing a core network, the core network providing wireless communication for mobile devices across at least a regional area, the non-SI device comprising - a non-SI private key constituting a pair with a non-SI public key; - a transceiver arranged for local transceiving according to the local communication protocol; - a processor arranged to execute an association sequence to establish an association with the SI, the association sequence comprising - providing the non-SI public key to the SI device via a first communication channel, - sharing a verification code with the SI device via a second communication channel for verifying that the SI device has obtained the non-SI public key, - the first and second communication channel being different and one of the channels being an out-of-band, OOB, channel, - providing proof of possession of the non-SI private key to the SI device via the first or the second communication channel, - receiving, from the SI device, a certificate related to the SI and comprising a signature as generated by a certification authority over at least part of the non-SI public key, the certificate enabling the non-SI device to access the core network via the local network and a gateway between the local network and the core network. - the local communication protocol defining protocol messages and wireless transceiving across a limited area, the non-SI device not comprising an SI and being arranged for cooperating with an SI device having access to the SI, - the SI comprising subscriber identity data of a subscriber to a provider for accessing a core network, the core network providing wireless communication for mobile devices across at least a regional area, the non-SI device comprising - a non-SI private key constituting a pair with a non-SI public key; - a transceiver arranged for local transceiving according to the local communication protocol; - a processor arranged to execute an association sequence to establish an association with the SI, the association sequence comprising - providing the non-SI public key to the SI device via a first communication channel, - sharing a verification code with the SI device via a second communication channel for verifying that the SI device has obtained the non-SI public key, - the first and second communication channel being different and one of the channels being an out-of-band, OOB, channel, - providing proof of possession of the non-SI private key to the SI device via the first or the second communication channel, - receiving, from the SI device, a certificate related to the SI and comprising a signature as generated by a certification authority over at least part of the non-SI public key, the certificate enabling the non-SI device to access the core network via the local network and a gateway between the local network and the core network.