Recommendation ITU-T X.1033 (X.gsiiso) addresses the aspects of security of the information service provided by the telecommunication operators. In the transformation from providing traditional basic telecommunication services to providing comprehensive information services, the operators expand their services to include content service and information and communication technology (ICT). The new services not only change the operational models but they also bring new security issues to be resolved. This Recommendation provides guidelines on the security of the individual information service provided by the telecommunication operators. The scope covers the classification of individual information service, the security requirements, the mechanisms, and the coordination.