Dynamic, Selective Obfuscation of Information for Multi-Party Transmission

• US 20090147958A1
• Filed: 12/08/2007
• Published: 06/11/2009
• Est. Priority Date: 12/08/2007
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Calcaterra, Jeffrey A., Hind, John R., Salahshour, Abdolreza
• Granted Patent: US 8,824,684 B2
• Time in Patent Office: Days
• US Class Current: 380/260
• CPC Class Codes: H04L 2209/16 Obfuscation or hiding, e.g. involving white box
• CPC Class Codes: H04L 9/0822 using key encryption key
• 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

Abstract

Selectively obfuscating, or obscuring, a portion or portions of information in a multi-party transmission. A user participating in a multi-party exchange signals a communication device (or proxy) that he will provide private information that is to be perceptible only to a subset of the other participants. This user also identifies that subset, preferably by providing a group identifier for a group in which that subset of participants are members. The communication device transmits a member-specific descriptor comprising an encrypted version of a group key, and uses this group key to encrypt the private information that is to be perceptible only to the subset. Device-specific characteristics of participant devices are used, in addition to user-provided data (such as a user'"'"'s log-on identifier and/or password), as input to create cryptographic key information. Only participants in the subset can decrypt the encrypted private information; other participants preferably receive a filler pattern of some type instead.

Claims

1. A computer-implemented method of selectively obfuscating information in a multi-party exchange, comprising:

obfuscating a segment received from a selected one of a plurality of participants in the multi-party exchange by encrypting the received segment in a manner that enables using cryptographic key information associated with the obfuscated segment to decrypt the obfuscated segment, for each one of the plurality of participants who is identified by the selected one as being permitted to perceive the segment, at a device used by that one for participating in the multi-party exchange and that prevents using the cryptographic key information to decrypt the obfuscated segment, for each remaining one of the plurality of participants who is not so identified, at a device used by that remaining one for participating in the multi-party exchange.

2. The method according to claim 1, wherein the obfuscated segment is transmitted to each identified one and to each remaining one of the participants.

3. The method according to claim 2, wherein the transmission occurs on a data channel of the multi-party exchange.

4. The method according to claim 1, wherein the cryptographic key information is transmitted to each identified one and to each remaining one of the participants.

5. The method according to claim 4, wherein the transmission occurs on a control channel of the multi-party exchange.

6. The method according to claim 1, wherein at least one segment received from one of the plurality of participants of the multi-party exchange is not obfuscated and is therefore perceptible to all other ones of the plurality of participants.

7. The method according to claim 1, wherein the cryptographic key information comprises a symmetric key that is recoverable, for decrypting the obfuscated segment, at the device used by each of the participants who is identified by the selected one but is not recoverable at the device used by any of the remaining participants who are not so identified.

8. The method according to claim 1, wherein the obfuscating occurs responsive to receiving, from a device used by the selected one for participating in the multi-party exchange, a signal indicating that the segment is to be obfuscated.

9. The method according to claim 1, wherein each identified one of the participants perceives the segment, responsive to using the cryptographic key information to decrypt the obfuscated segment, and each remaining one of the participants who is not identified by the selected one is provided with a filler pattern to perceive in place of perceiving the segment.

10. The method according to claim 1, wherein the segment is a vocal utterance and the multi-party exchange is a multi-party voice communication.

11. The method according to claim 10, wherein the obfuscating occurs responsive to receiving, from a phone device used by the selected one for participating in the multi-party voice communication, a signal indicating that the segment is to be obfuscated.

12. The method according to claim 1, wherein the segment is a typed message and the multi-party exchange is a multi-party chat session.

13. The method according to claim 1, wherein the segment is a spoken message and the multi-party exchange is a multi-party push-to-talk communication.

14. The method according to claim 1, wherein the segment is a portion of a text file and the multi-party exchange is a transmission of the text file to multiple parties.

15. The method according to claim 1, wherein the segment is a portion of a subscription feed and the multi-party exchange is a transmission of the subscription feed to multiple parties.

16. A method of selectively obfuscating information in a multi-party transmission, comprising:

determining a subset of a plurality of participants in the multi-party transmission who are to receive, in a perceptible form, a private segment of the information in the multi-party transmission;

obfuscating the private segment by encryption using a group encryption key corresponding to the subset;

encrypting a copy of the group encryption key for each of the participants in the subset, such that the group encryption key is only recoverable by the participants in the subset from that participant'"'"'s encrypted copy and is not recoverable, from any of the encrypted copies, by any of the participants not in the subset; and

transmitting the obfuscated private segment, and the encrypted copy for each of the participants, to all of the plurality of the participants in the multi-party transmission, whereby each of the participants in the subset can decrypt the transmitted obfuscated private segment, upon receipt thereof, using the group encryption key recovered by that participant but none of the participants not in the subset can decrypt the transmitted obfuscated private segment upon receipt thereof.

17. A system for selectively obfuscating information in a multi-party exchange, comprising:

an obfuscating segment received, from a selected one of a plurality of participants in the multi-party exchange, on a communication channel used for the multi-party exchange; and

an encryptor for encrypting the received segment in a manner that enables a decryptor using cryptographic key information associated with the obfuscated segment to decrypt the obfuscated segment, for each one of the plurality of participants who is identified by the selected one as being permitted to perceive the segment, at a device used by that one for participating in the multi-party exchange and that prevents a decryptor using the cryptographic key information from decrypting the obfuscated segment, for each remaining one of the plurality of participants who is not so identified, at a device used by that remaining one for participating in the multi-party exchange.

18. A computer program product for selectively obfuscating information in a multi-party transmission, the computer program product embodied on one or more computer-usable storage media and comprising computer-usable program code for:

determining a subset of a plurality of participants in the multi-party transmission who are to receive, in a perceptible form, a private segment of the information in the multi-party transmission;

obfuscating the private segment by encryption using a group encryption key corresponding to the subset;

encrypting a copy of the group encryption key for each of the participants in the subset, such that the group encryption key is only recoverable by the participants in the subset from that participant'"'"'s encrypted copy and is not recoverable, from any of the encrypted copies, by any of the participants not in the subset; and

transmitting the obfuscated private segment, and the encrypted copy for each of the participants, to all of the plurality of the participants in the multi-party transmission, whereby each of the participants in the subset can decrypt the transmitted obfuscated private segment, upon receipt thereof, using the group encryption key recovered by that participant but none of the participants not in the subset can decrypt the transmitted obfuscated private segment upon receipt thereof.

19. The computer program product according to claim 18, wherein the encrypting of the copy of the group encryption key for each of the participants in the subset uses, for each of the participants in the subset, information which corresponds to a device currently used by that participant and which is not transmitted to any of the participants in the multi-party transmission, thereby enabling the participant to recover the group encryption key from that currently-used device.

20. The computer program product according to claim 19, wherein:

the information which corresponds to the currently-used device comprises a private obfuscation key that is securely stored on the device; and

a public obfuscation key that is cryptographically associated with the private obfuscation key is used in the encrypting of the copy of the group encryption key, enabling the encrypted copy to be recovered by the participant currently using the device.

21. The computer program product according to claim 18, wherein the obfuscated segment has associated therewith an expiration timestamp, and wherein the transmitted obfuscated segment cannot be decrypted by any of the participants in the multi-party transmission after the expiration timestamp expires.