Single-Key to Multi-Key Functional Encryption with Polynomial Loss

Conference paper

DOI: 10.1007/978-3-662-53644-5_16

Part of the Lecture Notes in Computer Science book series (LNCS, volume 9986)
Cite this paper as:
Garg S., Srinivasan A. (2016) Single-Key to Multi-Key Functional Encryption with Polynomial Loss. In: Hirt M., Smith A. (eds) Theory of Cryptography. TCC 2016. Lecture Notes in Computer Science, vol 9986. Springer, Berlin, Heidelberg


Functional encryption (FE) enables fine-grained access to encrypted data. In a FE scheme, the holder of a secret key \(\mathsf {FSK}_f\) (associated with a function f) and a ciphertext c (encrypting plaintext x) can learn f(x) but nothing more.

An important parameter in the security model for FE is the number of secret keys that adversary has access to. In this work, we give a transformation from a FE scheme for which the adversary gets access to a single secret key (with ciphertext size sub-linear in the circuit for which this secret key is issued) to one that is secure even if adversary gets access to an unbounded number of secret keys. A novel feature of our transformation is that its security proof incurs only a polynomial loss.

Copyright information

© International Association for Cryptologic Research 2016

Authors and Affiliations

  1. 1.University of CaliforniaBerkeleyUSA

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