Methods And Apparatuses For Maintaining Secure Communication Between A Group Of Users In A Social Network

• US 20130179951A1
• Filed: 01/06/2012
• Published: 07/11/2013
• Est. Priority Date: 01/06/2012
• Status: Abandoned Application

• Current Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Original Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Inventors: Broustis, Ioannis, Cakulev, Violeta, Sundaram, Ganapathy Subramanian
• Application Number:
  US13/345,438
• Publication Number:
  US 20130179951A1
• Time in Patent Office: Days
• US Class Current: 726/6
• CPC Class Codes: G06F 21/602 Providing cryptographic facilities or services
• CPC Class Codes: G06F 2221/2137 Time limited access, e.g. to a computer or data
• CPC Class Codes: H04L 63/0435 wherein the sending and receiving network entities apply symmetric encryption, i.e. same key used for encryption and decryption cryptographic mechanisms or cryptographic arrangements for symmetric key encryption H04L9/06
• CPC Class Codes: H04L 63/065 for group communications cryptographic mechanisms or cryptographic arrangements for key management involving conference or group key H04L9/0833
• CPC Class Codes: H04L 9/0833 involving conference or group key network architectures or network communication protocols for key management in group communication in a packet data network H04L63/065
• CPC Class Codes: H04L 9/0841 involving Diffie-Hellman or related key agreement protocols
• CPC Class Codes: H04L 9/3066 involving algebraic varieties, e.g. elliptic or hyper-elliptic curves

Abstract

Embodiments address various methods and apparatuses that attempt to minimize the time that the security communication between group members may be at risk due to a user joining or leaving. For example, embodiments include methods of minimizing the time for which a joining member receives a secure commonly shared key and other embodiments include methods of minimizing the time that a user leaving the group has access to data shared within the group through updating the secure commonly shared key.

Claims

1. A method of maintaining security between a group of users in a social network, comprising:

identifying, by a social network host, a group of users, U₁ . . . U_m of the social network who securely communicate between each other using an initial commonly derived shared key that the social network host can not derive;

adding, by the social network host, at least one additional user U<sub>m−

1</sub> to the group of users of the social network, wherein the at least one additional user cannot derive the initial shared key; and

storing shared data D₁ sent by one user in said group of users, the shared data being encrypted by an updated commonly derived shared key.

2. The method of claim 1, wherein the updated commonly derived shared key is derived by the group of users in response to adding the at least one additional user.

6. The method of claim 1, wherein the updating of the at least one published parameter is performed by a user agent associated with at least one user of the group of users.

7. The method of claim 6, wherein the user agent is associated with user U₁ and/or U_m.

8. The method of claim 1, further comprising:

sending a temporary key to users U₂ . . . U_m+1 prior to the updating the at least one published parameter step.

9. The method of claim 8, further comprising:

sending the temporary key to users U₂ . . . U_m using the initial commonly derived shared key.

10. The method of claim 1, further comprising:

sending the initial commonly derived shared key to user U_m+1 prior to the at least updating parameter step.

3-5. -5. (canceled)

11. A method of maintaining security between a group of users in a social network, comprising:

identifying a group of users, U₁ . . . U_m of the social network, by a social network host, who securely communicate between each other using a commonly derived shared key that the social network host can not derive;

removing a user U_i from the group of users who securely communicate between each other; and

updating at least one published parameter on which the updated commonly derived shared key is to be based, wherein the group of users minus the removed user can now securely communicate between each other without the removed user being able to derive the commonly shared key without the social network host being able to derive the commonly shared key.

13. The method of claim 11, wherein the at least one published parameter is either X_i−

1 or X_i+1 corresponding to user U<sub>i−

1</sub> or U_i+1, respectively, and defined as X_i=a_i(a_i+1P−

a<sub>i−

1</sub>P), where a_i is a secret random number and P is a commonly agreed point on an elliptic curve E′

.

14. The method of claim 11, wherein the updating the at least one published parameter is performed by a user agent corresponding to at least one user of the group of users.

15. The method of claim 14, wherein a user agent corresponds to user U_i+1 and/or U_i−

1.

16. The method of claim 11, further comprising:

sending a temporary key to users U₂ . . . U<sub>i−

1</sub> and U_i+1 . . . U_m prior to the updating the at least one published parameter step.

12. (canceled)

17. A method of maintaining security between a group of users in a social network, comprising:

identifying a group of users, U₁ . . . U_m of the social network, by a social network host, who securely communicate between each other using a initial commonly derived shared key that the social network host can not derive;

adding at least one additional user U_m+1, who can not derive the shared key, to the group of users of the social network, by the social network host;

switching users U_m and U_m+1 upon the expiration of a timer, wherein user U_m did not update its X_m value by the end of the timer; and

updating at least the X_m value, now corresponding to the joining user on which an updated commonly derived shared key is to be based, wherein the group of users and the additional new user, except for switched user U_m+1, can now securely communicate between each other using the updated commonly derived shared key based on the updated X_m value, without the social network host being able to derive the updated commonly shared key.

18. (canceled)

19. An apparatus comprising:

a memory; and

at least one processor coupled to the memory and configured to;

identify a group of users, U₁ . . . U_m of the social network, by a social network host who securely, communicate between each other using an initial commonly derived shared key that the social network host can not derive;

add at least one additional user U_m+1 who can not derive the shared key to the group of users of the social network, by the social network host; and

update at least one published parameter on which an updated commonly derived shared key is to be based, wherein the group of users and the additional user can now securely communicate between each other using the updated commonly derived shared key based on the updated at least one published parameter without the social network host being able to derive the updated commonly shared key.

20. An apparatus comprising:

a memory; and

at least one processor coupled to the memory and configured to;

identify a group of users, U₁ . . . U_m of the social network, by a social network host who securely, communicate between each other using a commonly derived shared key that the social network host can not derive;

remove a user U_i from the group of users who securely communicate between each other; and

update at least one published parameter on which an updated commonly derived shared key is to be based, wherein the group of users minus the removed user can now securely communicate between each other without the removed user being able to derive the updated commonly shared key and without the social network host being able to derive the updated commonly shared key.

21. A method of maintaining security between a first user and additional users in a social network, comprising:

securely communicating between members of a first group of users that includes the first user and a first number of the additional users using an initial commonly shared key derived by the first user from parameters provided by the first number of additional users;

deriving an updated commonly derived shared key by the first user from parameters provided by a second different number of additional users; and

securely communicating between members of a second group of users that includes the first user and the second number of additional users.

22. The method of claim 21, further comprising the first user publishing at least one parameter from which the first user and the additional users derive the updated common derived shared key.

23. The method of claim 22, wherein the at least one published parameter is either X₁ or X_m corresponding to user U₁ or U_m, respectively, and defined as X_i=a_i(a_i+1P−

a<sub>i−

1</sub>P), where a_i is a secret random number and P is a commonly agreed point on an elliptic curve E′

.

24. The method of claim 22, further comprising:

identifying a user of the first group of users who is online most often; and

dynamically defining the identified user as user U_m of the first group of users, prior to the publishing step.

25. The method of claim 21, wherein the second group includes the members of the first group and a new user.