According to an example aspect of the present invention, there is provided an apparatus comprising at least one processing core, at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processing core, cause the apparatus at least to establish a user equipment context for a user equipment registered with the apparatus, the user equipment context being associated with an identity of the user equipment, determine that a plurality of network messages comprising the identity of the user equipment as sender fail a network message integrity process, and trigger, responsive to the determination, at least one of: 1) sending a paging message to the user equipment, and 2) initiating an authentication process with a sender of the network messages, and deletion the user equipment context as a response to successful completion of the authentication process.