Wireless communication system

• US 20050201564A1
• Filed: 09/28/2004
• Published: 09/15/2005
• Est. Priority Date: 03/09/2004
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Nomura, Yuji, Kayashima, Naoshi, Nagano, Yuuji
• Granted Patent: US 7,519,184 B2
• Time in Patent Office: Days
• US Class Current: 380/283
• CPC Class Codes: H04L 2209/80 Wireless network architectures or network communication protocols for wireless network security H04W12/00
• CPC Class Codes: H04L 63/068 using time-dependent keys, e.g. periodically changing keys cryptographic mechanisms or cryptographic arrangements for controlling usage of secret information H04L9/088
• CPC Class Codes: H04L 9/0891 Revocation or update of secret information, e.g. encryption key update or rekeying
• CPC Class Codes: H04W 12/04 Key management, e.g. using generic bootstrapping architecture [GBA]
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A small-scale wireless communication system offering advanced security level. An encryption key memory of an access point stores an encryption key list of a plurality of different encryption keys. A change information transmitter periodically transmits change information to a terminal by radio, the change information requesting the change of encryption key. An encryption key selector selects an encryption key from the encryption key list under a rule when the change information transmitter transmits the change information. A terminal-side encryption key memory of the terminal stores a terminal-side encryption key list which is the same as the encryption key list. A change information receiver receives the change information from the access point. Upon reception of the change information, a terminal-side encryption key selector selects an encryption key from the terminal-side encryption key list under a rule which is the same as the rule which the encryption key selector used to select the encryption key.

Claims

1. A wireless communication system for encrypting and decrypting communication data with an encryption key in wireless communication, comprising:

an access point comprising;

encryption key memory means for storing an encryption key list of a plurality of different encryption keys;

change information transmission means for periodically transmitting change information by radio, the change information requesting that an encryption key being used for encrypting the communication data should be changed; and

encryption key selector for selecting the encryption key from the encryption key list under a rule when the change information is transmitted by radio; and

a terminal comprising;

terminal-side encryption key memory means for storing a terminal-side encryption key list which is the same as the encryption key list;

change information reception means for receiving the change information; and

terminal-side encryption key selection means for selecting the encryption key from the terminal-side encryption key list under a rule which is the same as the rule, in response to the change information.

2. The wireless communication system according to claim 1, wherein:

the access point further comprises;

list update means for updating the encryption key list; and

list transmission means for transmitting the encryption key list updated; and

the terminal further comprises;

list reception means for receiving the encryption key list updated; and

list storing means for storing the encryption key list received, in the terminal-side encryption key memory means.

3. The wireless communication system according to claim 2, wherein:

the encryption key memory means has two memory regions; and

the list update means stores the encryption key list updated, in one of the memory regions which does not store the encryption key list being used.

4. The wireless communication system according to claim 2, wherein:

the terminal-side encryption key memory means has two memory regions; and

the list storing means stores the encryption key list received, in one of the memory regions which does not store the terminal-side encryption key list being used.

5. The wireless communication system according to claim 1, wherein:

the access point further comprises communication data retaining means for temporarily keeping communication data to be transmitted, after transmission of the change information; and

the terminal further comprises terminal-side communication data retaining means for temporarily keeping communication data to be transmitted, after reception of the change information.

6. The wireless communication system according to claim 5, wherein:

the access point further comprises communication data releasing means for transmitting the communication data being kept, after reception of change completion information from the terminal, the change completion information indicating completion of change of the encryption key; and

the terminal further comprises;

completion information transmission means for transmitting the change completion information; and

terminal-side communication data releasing means for transmitting the communication data being kept, after transmission of the change completion information.

7. The wireless communication system according to claim 1, wherein the terminal further comprises response signal transmission means for storing a response signal in Type and Subtype subfields of a frame control field of a MAC frame and transmitting the MAC frame to the access point, the response signal indicating reception of the change information.

8. An access point for encrypting and decrypting communication data with an encryption key in wireless communication, comprising:

encryption key memory means for storing an encryption key list of a plurality of different encryption keys;

change information transmission means for periodically transmitting change information by radio, the change information requesting that an encryption key being used for encrypting the communication data should be changed; and

encryption key selection means for selecting the encryption key from the encryption key list under a rule when the change information is transmitted by radio.

9. A terminal for encrypting and decrypting communication data with an encryption key in wireless communication, comprising:

terminal-side encryption key memory means for storing a terminal-side encryption key list which is the same as an encryption key list of a plurality of different encryption keys being stored in an access point;

change information reception means for periodically receiving change information from the access point, the change information requesting that an encryption key being used for encrypting the communication data should be changed; and

terminal-side encryption key selection means for selecting the encryption key from the terminal-side encryption key list under a rule which is the same as a rule used by the access point to select the encryption key from the encryption key list, in response to the change information.