# Supporting Privacy of Computations in Mobile Big Data Systems +
###### Abstract
: +1-607-592-0467  
Footnote †: journal: Future Internet  
[PERSON]  
1 Qualcomm Research, Santa Clara, CA 95051, USA; [EMAIL_ADDRESS]  
2 School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA 23 Department of Computer Science, University of Texas at Dallas, Richardson, TX 75080, USA 3  
4 Correspondence: [EMAIL_ADDRESS]; Tel. : +1-607-592-0467  
Footnote †: journal: Future Internet  
[PERSON]  
1 Qualcomm Research, Santa Clara, CA 95051, USA; sriramnp@@ti.qualcomm.com  
2 School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA 23 Department of Computer Science, University of Texas at Dallas, Richardson, TX 75080, USA 3  
4 Correspondence: [EMAIL_ADDRESS]; Tel. : +1-607-592-0467  
Footnote †: journal: Future Internet  
[PERSON]  
1 Qualcomm Research, Santa Clara, CA 95051, USA; sriramnp@@ti.qualcomm.com  
2 School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA 23 Department of Computer Science, University of Texas at Dallas, Richardson, TX 75080, USA 3  
4 Correspondence: [EMAIL_ADDRESS]; Tel. : +1-607-592-0467  
Footnote †: journal: Future Internet  
[PERSON]  
1 Qualcomm Research, Santa Clara, CA 95051, USA; sriramnp@@ti.qualcomm.com  
2 School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA 23 Department of Computer Science, University of Texas at Dallas, Richardson, TX 75080, USA 3  
4 Correspondence: [EMAIL_ADDRESS]; Tel. : +1-607-592-0467  
Footnote †: journal: Future Internet  
[PERSON]  
1 Qualcomm Research, Santa Clara, CA 95051, USA; [EMAIL_ADDRESS]  
2 School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA 23 Department of Computer Science, University of Texas at Dallas, Richardson, TX 75080, USA 3 While mobile devices store \"private information\" of users such as location, payment, health data, _etc._, they may also contribute \"semi-public information\" (which may include crowdsourced data such as transit, traffic, nearby points of interests, _etc._) for data analytics. In such a scenario, a mobile device may seek to obtain the result of a computation, which may depend on its private inputs, crowdsourced data from other mobile devices, and/or any \"public inputs\" from other servers on the Internet. However, the mobile device may not perform the computation on its own: (i) due to resource constraints (in terms of computing, memory, network, power, _etc._); and/or (ii) due to the restrictions (privacy, legal requirements, _etc._) on the servers to share data from one user with others. Alternatively, exchange of data in \" plain text form\" between the mobile client and the cloud service provider to carry out the computations will also result in complete loss of data privacy. Homomorphic encryption [2] is one of the approaches to address the problem of preserving data privacy. It can allow the cloud service providers to perform specific computations directly on the encrypted client data, without requiring private decryption keys. To perform any arbitrary computation on encrypted data, fully homomorphic encryption (FHE) schemes (e.g., [3; 4; 5]) have been proposed recently. However, FHE schemes are currently not suitable for mobile cloud computing or big data applications due to extremely large cipher text size and computational requirements beyond the capabilities of mobile devices today. Therefore, there exists a need for a more efficient alternative suitable for mobile systems. We consider [PERSON]'s garbled circuits approach [6; 7] in our work as a potential alternative to FHE schemes to drastically reduce the ciphertext size. In general, any computation can be represented using a Boolean circuit, for which, there exists a corresponding garbled circuit [6; 7; 8; 9]. Each gate in a garbled circuit can be unlocked using a pair of input \"wire keys\" to reveal an output wire key, which, in turn, serves as an input wire key for unlocking the subsequent gate in the next level of the circuit, and so on.