There is provided mechanisms for enabling secure communication between a first communications device and a second communications device. A method is performed by the first communications device. The method comprises performing a network attachment procedure with an authentication server. The method comprises establishing, during the network attachment procedure, a shared secret between the first communications device and the authentication server. The shared secret is established by running an authentication and key agreement protocol as part of the network attachment procedure with a network access identity of the first communications device as input. The method comprises deriving an application level shared key for the first communications device from the shared secret. The shared key is to be used for secure communication between the first communications device and the second communications device.