Private Functional Encryption: Indistinguishability-Based Definitions and Constructions from Obfuscation

• Type: Article in International Conference Proceedings Book
• Date: 2016

Authors

Arriaga, A (Author) Other; Barbosa, M (Author) FCUP; Farshim, P (Author) Other

Conference proceedings International

Title: PROGRESS IN CRYPTOLOGY - INDOCRYPT 2016

Pages: 227-247

17th International Conference on Cryptology in India (INDOCRYPT)

Kolkata, INDIA, DEC 11-14, 2016

Indexing

ISI Web of Knowledge - 2 Citations

Scopus - 2 Citations

Other information

Authenticus ID: P-00M-5X4

DOI: 10.1007/978-3-319-49890-4_13

Abstract (EN): Private functional encryption guarantees that not only the information in ciphertexts is hidden but also the circuits in decryption tokens are protected. A notable use case of this notion is query privacy in searchable encryption. Prior privacy models in the literature were fine-tuned for specific functionalities (namely, identity-based encryption and inner-product encryption), did not model correlations between ciphertexts and decryption tokens, or fell under strong uninstantiability results. We develop a new indistinguishability-based privacy notion that overcomes these limitations and give constructions supporting different circuit classes and meeting varying degrees of security. Obfuscation is a common building block that these constructions share, albeit the obfuscators necessary for each construction are based on different assumptions. In particular, we develop a composable and distributionally secure hyperplane membership obfuscator and use it to build an inner-product encryption scheme that achieves an unprecedented level of privacy, positively answering a question left open by Boneh, Raghu-nathan and Segev (ASIACRYPT 2013) concerning the extension and realization of enhanced security for schemes supporting this functionality.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 21