Methods And Apparatuses For Secure Information Sharing In Social Networks Using Randomly-Generated Keys

• US 20130179679A1
• Filed: 01/06/2012
• Published: 07/11/2013
• Est. Priority Date: 01/06/2012
• Status: Active Grant

• Current Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Original Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Inventors: Broustis, Ioannis, Cakulev, Violeta, Sundaram, Ganapathy Subramanian
• Granted Patent: US 8,769,259 B2
• Time in Patent Office: Days
• US Class Current: 713/152
• CPC Class Codes: H04L 9/0822 using key encryption key

Abstract

There can be problems with the security of social networking communications. For example, there may be occasions when a number of friends wish to communicate securely through a social network infrastructure, such that non-trusted 3^rd-party entities, such as a Social Network Operator or host that provides the application infrastructure, does not overhear the communication. In response to the above problems, embodiments presented propose a set of innovative, lightweight solutions, considering that in certain scenarios the Social Network Operator may not be a trusted entity. Embodiments of the present invention are directed to methods and apparatuses for secure information sharing in social networks using random keys.

Claims

1. A method for secure information sharing in a social network, comprising:

authorizing a user of the social network to obtain at least one message including data intended to be shared with the user of the social network, wherein the authorization is for access to the at least one message by a resource owner of the at least one message;

receiving the at least one message, by the user;

extracting a first ciphertext C_i and a second ciphertext C_D1 from the at least one message, by a processor;

decrypting the first ciphertext C_i with a second key to obtain a random key K_R, by a processor; and

decrypting the second ciphertext C_D1 using the random key K_R to obtain the data D₁ intended to be shared, by a processor.

2. The method of claim 1, wherein the second key is a private key of the user corresponding to a known public key of the user.

3. The method of claim 2, wherein the at least one message comprises the following structure:

m₁=C_D1∥

{U₂, C₂}∥

. . . ∥

{U_M, C_M}, wherein C_D1 is the second ciphertext of D₁ encrypted by K_R, and {U₂, C₂}∥

. . . {U_M, C_M} is the user identified concatenated first ciphertext C_i for users 2 to M, where each first ciphertext is the random key K_R encrypted with the public key of the identified user.

4. The method of claim 1, wherein the second key is a group public key.

5. The method of claim 4, further comprising:

securely obtaining the group public key from a key generation function entity.

6. The method of claim 1, wherein the second key is a shared commonly derived key.

7. The method of claim 6, wherein the shared commonly derived key is based on a secret random number generated by the user and key components from other users, and the key derivation is based on operations in a finite group, wherein the other users are users that are also authorized to derive the shared common key.

8. The method of claim 7, wherein the finite group comprises points on a non-supersingular elliptic curve, and the key components are derived from a fixed known point on the curve, and the secret random numbers are random integers.

9. The method of claim 1, further comprising:

receiving notification that at least one message including data intended to be shared with the user of the social network is present at the social network.

10. The method of claim 1, further comprising:

sending update requests as to whether there is at least one message including data intended to be shared with the user of the social network present at the social network;

receiving confirmation that there is at least one message including data intended to be shared with the user of the social network present at the social network.

11. The method of claim 1, wherein authorization is based on an OAuth protocol.

12. The method of claim 1, further comprising:

receiving validation of the access token prior to receiving the at least one message.

13. The method of claim 1, further comprising:

validating the integrity of the at least one message by using a known public key of the resource owner.

14. An apparatus comprising:

a memory; and

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

authorize a user of the social network to obtain at least one message including data intended to be shared with the user of the social network, wherein authorization is for access to the at least one message by a resource owner of the at least one message;

receive the at least one message;

extract a first ciphertext C_i and a second ciphertext C_D1 from the at least one message;

decrypt the first ciphertext C_i to obtain a random key K_R; and

decrypt the second ciphertext C_D1 using the random key K_R to obtain the data D₁ intended to be shared.

15. A method for secure information sharing in a social network, comprising:

selecting, by a user of the social network, a random key K_R;

encrypting data intended to be shared with a set of users of the social network with the random key K_R to create a first ciphertext C_D1, by a processor;

encrypting the random key K_R with a second key to create a second ciphertext C_i, by a processor;

creating a message including both the first and second ciphertexts, by a processor; and

sending the created message to a storage location of the social network.

16. The method of claim 15, wherein the second key is a public key of a user of the set of users, such that C_i equals the encryption of the random key K_R with the public key of the user.

17. The method of claim 15, wherein the second key is a group public key securely obtainable from a key generation function entity.

18. The method of claim 15, wherein the second key is a shared commonly derived key based on a secret random number and a commonly agreed point on an elliptic curve.

19. An apparatus comprising:

a memory; and

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

select, by a user of the social network, a random key K_R;

encrypt data intended to be shared with a set of users of the social network with the random key K_R to create a first ciphertext C_D1;

encrypt the random key K_R with a second key to create a second ciphertext C_i;

create a message including both the first and second ciphertexts; and

send the created message to a storage location of the social network.

20. A system for secure information sharing in social networks, comprising:

a first social network user configured to

encrypt data to be shared between a set of social network users, using a random key,

generate a set of ciphertexts by encrypting the random key with a second key,

form a message including the encrypted data and the generated set of ciphertexts, and

send the formed message to a social network host;

the social network host configured to

receive and store the formed message, and

send the formed message to at least one of the set of social network users; and

the set of social network users, each configured to

receive the formed message;

extract at least one ciphertext from the formed message;

decrypt the at least one ciphertext using a corresponding key to the second key to obtain the random key; and

decrypt data from the formed message using the decrypted random key.