A method for authenticating a wireless communications device to a network slice of a communications network is provided. The wireless communications device has one or more attributes associated with it, at least one of the one or more attributes fulfilling an attribute-based access policy of the network slice. The method is performed by a slice manager of the communications network and comprises sending a secret key to the wireless communications device, sending an encrypted access key to the wireless communications device, the encrypted access key being encrypted using the access policy, such that a secret key generated based at least one attribute that fulfill the attribute-based access policy can decrypt the encrypted access key.