Title
Adaptively Secure and Succinct Functional Encryption: Improving Security and Efficiency, Simultaneously.
Abstract
Functional encryption (FE) is advanced encryption that enables us to issue functional decryption keys where functions are hard-wired. When we decrypt a ciphertext of a message m by a functional decryption key where a function f is hardwired, we can obtain f(m) and nothing else. We say FE is selectively or adaptively secure when target messages are chosen at the beginning or after function queries are sent, respectively. In the weakly-selective setting, function queries are also chosen at the beginning. We say FE is single-key/collusion-resistant when it is secure against adversaries that are given only-one/polynomiallymany functional decryption keys, respectively. We say FE is sublinearlysuccinct/succinct when the running time of an encryption algorithm is sublinear/poly-logarithmic in the function description size, respectively. In this study, we propose a generic transformation from weakly-selectively secure, single-key, and sublinearly-succinct (we call "building block") PKFE for circuits into adaptively secure, collusion-resistant, and succinct (we call "fully-equipped") one for circuits. Our transformation relies on neither concrete assumptions such as learning with errors nor indistinguishability obfuscation (IO). This is the first generic construction of fully-equipped PKFE that does not rely on IO. As side-benefits of our results, we obtain the following primitives from the building block PKFE for circuits: (1) laconic oblivious transfer (2) succinct garbling scheme for Turing machines (3) selectively secure, collusion-resistant, and succinct PKFE for Turing machines (4) low-overhead adaptively secure traitor tracing (5) key-dependent message secure and leakage-resilient public-key encryption. We also obtain a generic transformation from simulation-based adaptively secure garbling schemes that satisfy a natural decomposability property into adaptively indistinguishable garbling schemes whose online complexity does not depend on the output length.
Year
DOI
Venue
2018
10.1007/978-3-030-26954-8_17
ADVANCES IN CRYPTOLOGY - CRYPTO 2019, PT III
Field
DocType
Volume
Computer science,Computer network,Functional encryption
Journal
11694
ISSN
Citations 
PageRank 
0302-9743
0
0.34
References 
Authors
0
4
Name
Order
Citations
PageRank
Fuyuki Kitagawa147.86
Ryo Nishimaki213114.91
Keisuke Tanaka315.76
Takashi Yamakawa4129.35