REGISTERING USER EQUIPMENT WITH A VISITED PUBLIC LAND MOBILE NETWORK

User equipment is registered with a visited public land mobile network, VPLMN, in a process including: producing at the user equipment a concealed identifier; producing at the user equipment a freshness code; and sending by the user equipment to the VPLMN the concealed identifier and the freshness code; receiving by the user equipment an identity request from the VPLMN indicating that the long-term identifier must be transmitted to the VPLMN in a non-concealed form; receiving by the user equipment from the VPLMN a permission authenticator; and verifying at the user equipment if the permission authenticator has been formed with a cryptographic authentication of the home public land mobile network, HPLMN, and the user equipment or a subscription module at the user equipment indicating permission to transmit the long-term identifier to the VPLMN in the non-concealed form and if yes, transmitting the long-term identifier to the VPLMN in the non-concealed form.