Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a cellular modem may transmit, to an applications processor, an indication to use a non-Third Generation Partnership Project (non-3GPP) interworking function (N3IWF) for non-access stratum (NAS) signaling. Accordingly, the cellular modem may establish a first virtual interface with the applications processor. The cellular modem may further perform an Internet Key Exchange (IKE) procedure with a core network using the first virtual interface and the N3IWF and transmit a key generated during the IKE procedure to the applications processor. Numerous other aspects are described.