CommonContacts allows two users to collaboratively discover common entries in their address books without disclosing any other information about their contacts. The application uses a secure computation framework built using Yao's garbled circuit technique. All computation involving private data is performed on encrypted data so no information is released to the other party (other than what can be inferred from the result).
Short Description [PDF, 2 pages]
Yan Huang, Peter Chapman, and David Evans. Privacy-Preserving Applications on Smartphones. 6th USENIX Workshop on Hot Topics in Security (HotSec 2011), San Francisco. 9 August 2011. [PDF, 6 pages]The secure computation framework used to build these applications is described in this paper:
Yan Huang, David Evans, Jonathan Katz, and Lior Malka. Faster Secure Two-Party Computation Using Garbled Circuits, 20th USENIX Security Symposium, San Francisco, CA. 8-12 August 2011. [PDF, 16 pages]
Funding. This work was supported in part by grants from the Air Force Office of Scientific Research (MURI), National Science Foundation, and DARPA. We thank Google for providing Nexus One phones.