Abstract: Provided is a method for managing a group key in a key distribution center. The method includes: receiving a key request from a mobile device; generating a private key for the mobile device using information about a withdrawal time included in the key request; generating a public key and a verification key for the mobile device; and transmitting at least one key including the generated key to the mobile device.

Abstract: The present invention relates to a method and apparatus for updating a key for encrypting multicast data in a wireless communication system. The method of the present invention is characterized by comprising: an information receiving step of receiving information on a group entry time and a group exit time from users who have newly entered an arbitrary group including at least one subgroup; a grouping step of grouping the users using the information on the group entry time and the group exit time; and a key transmission step of either transmitting, to the newly-entered users, keys related to the group and the subgroups, or updating, for the remaining users of the subgroups, both the key related to the subgroup to which the user exiting the group belongs and the key of the group and then transmitting the updated keys to the users of the subgroups.

Abstract: A system and method of updating a key based on communication and security damage costs are provided. The key updating system for group communication between a plurality of group members, includes a key update cycle determining unit to determine a key update cycle based on a communication cost and a security damage cost, and a key updating unit to perform a key updating with respect to one or more group members of the group communication based on the determined key update cycle.

Abstract: Provided is a method for managing a group key in a key distribution center. The method includes: receiving a key request from a mobile device; generating a private key for the mobile device using information about a withdrawal time included in the key request; generating a public key and a verification key for the mobile device; and transmitting at least one key including the generated key to the mobile device.

Abstract: The present invention relates to a method and apparatus for updating a key for encrypting multicast data in a wireless communication system. The method of the present invention is characterized by comprising: an information receiving step of receiving information on a group entry time and a group exit time from users who have newly entered an arbitrary group including at least one subgroup; a grouping step of grouping the users using the information on the group entry time and the group exit time; and a key transmission step of either transmitting, to the newly-entered users, keys related to the group and the subgroups, or updating, for the remaining users of the subgroups, both the key related to the subgroup to which the user exiting the group belongs and the key of the group and then transmitting the updated keys to the users of the subgroups.

Abstract: A system and method of updating a key based on communication and security damage costs are provided. The key updating system for group communication between a plurality of group members, includes a key update cycle determining unit to determine a key update cycle based on a communication cost and a security damage cost, and a key updating unit to perform a key updating with respect to one or more group members of the group communication based on the determined key update cycle.