Method and apparatus for updating a group key in a wireless communication system

Patent metadata

Field	Value
Publication number	US-9294275-B2
Application number	US-201214131590-A
Country	US
Kind code	B2
Filing date	Jul 9, 2012
Priority date	Jul 8, 2011
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

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.

First claim

The invention claimed is:

1. A key update method of encrypting multicast data in a wireless communication system, the method comprising:
receiving, by an apparatus, information on group entry times and group entry times of users entering newly a certain group including at least one subgroup;
sorting, by the apparatus, the users into the at least one subgroup based on the group entry and departure times;
sending, by the apparatus, the users a group key of the group and subgroup keys of the corresponding subgroups respectively;
updating, by the apparatus, when a user departs from the group, the subgroup key of the subgroup from which the user departs and the group key, and
transmitting, by the apparatus, the updated subgroup key and group key to the users remained in the group.

2. The method of claim 1 , wherein the sorting of the users comprises:
sorting the users into a departed user group and a remained user group and deleting the departed user group; and
including the newly entering user in the remained user group based on the group departure time.

3. The method of claim 2 , wherein the including of the newly entering user comprises including the newly entering the user in the remained user group according to a remainder value obtained by diving the group departure time of the newly entering user by a number of the subgroups.

4. The method of claim 2 , wherein the including of the newly entering users comprises:
determining whether the newly entering user is the user to depart from the group in a predetermined time; and
including, when the newly entering user is the user to depart from the group in the predetermined time, the newly entering user in a short term departure group.

5. The method of claim 4 , wherein the including of the newly entering users comprises including, when the newly entering user is not the user to depart from the group in the predetermined time, the newly entering user in the remained user group.

6. An apparatus of updating and delivering keys encrypting multicast data in a wireless communication system, the apparatus comprising:
an interface unit configured to receive information on group entry times and group entry times of users entering newly a certain group including at least one subgroup; and
at least one hardware processor configured to:
sort the users into the at least one subgroup based on the group entry and departure times, sends the users a group key of the group and subgroup keys of the corresponding subgroups respectively,
update, when a user departs from the group, the subgroup key of the subgroup from which the user departs and the group key, and
transmit the updated subgroup key and group key to the users remained in the group.

7. The apparatus of claim 6 , wherein the at least one hardware processor is further configured to:
sort the users into a departed user group and a remained user group,
delete the departed user group, and
include the newly entering user in the remained user group based on the group departure time.

8. The apparatus of claim 7 , wherein the at least one hardware processor is further configured to include the newly entering the user in the remained user group according to a remainder value obtained by diving the group departure time of the newly entering user by a number of the subgroups.

9. The apparatus of claim 6 , wherein the at least one hardware processor is further configured to:
determine whether the newly entering user is the user to depart from the group in a predetermined time and
include, when the newly entering user is the user to depart from the group in the predetermined time, the newly entering user in a short term departure group.

10. The apparatus of claim 9 , wherein the at least one hardware processor is further configured to include, when the newly entering user is not the user to depart from the group in the predetermined time, the newly entering user in the remained user group.

Assignees

• Suh Kyung Joo
• Choi Sung Ho
• Bae Beom Sik
• Baek Young Kyo
• Jeong Sang Soo
• Seo Seung Woo
• Park Young Hoon
• Je Dong Hyun
• Samsung Electronics Co Ltd
• Snu R&Db Foundation

Inventors

• Suh Kyung Joo
• Choi Sung Ho
• Bae Beom Sik
• Baek Young Kyo
• Jeong Sang Soo
• Seo Seung Woo
• Park Young Hoon
• Je Dong Hyun

Classifications

• H04L9/0836

  using tree structure or hierarchical structure · CPC title

• H04W12/04

  Key management, e.g. using generic bootstrapping architecture [GBA] · CPC title

• H04L2209/601

  Broadcast encryption · CPC title

• H04L9/0891 Primary

  Revocation or update of secret information, e.g. encryption key update or rekeying · CPC title

• H04L63/065

  for group communications (cryptographic mechanisms or cryptographic arrangements for key management involving conference or group key H04L9/0833) · CPC title