A method of secure charging for a device-to-device service may comprise: recording charging information of a device-to-device service between a first user equipment and a second user equipment, wherein the charging information is associated at least with the first user equipment; generating a first report comprising the charging information, wherein the first report is protected by a security key of the first user equipment; and sending the first report to a network node by the first user equipment, wherein the first report is used for charging for the device-to-device service together with a second report generated at the second user equipment, and wherein the second report comprises charging information associated at least with the device-to-device service of the second user equipment and is protected by a security key of the second user equipment.