Paradigms in Cryptology – Mycrypt 2016. Malicious and Exploratory Cryptology
Springer
Lecture Notes in Computer Science
347-363
Yes
International
978-3-319-61272-0
International Conference on Cryptology in Malaysia 2016 (Mycrypt 2016)
from 01-12-2016 to 02-12-2016
Malaysia
[en] functional encryption
[en] Functional encryption (FE) allows an authority to issue tokens associated with various functions, allowing the holder of some token for function f to learn only f(𝖣)f(D) from a ciphertext that encrypts 𝖣D . The standard approach is to model f as a circuit, which yields inefficient evaluations over large inputs. Here, we propose a new primitive that we call updatable functional encryption (UFE), where instead of circuits we deal with RAM programs, which are closer to how programs are expressed in von Neumann architecture. We impose strict efficiency constrains in that the run-time of a token 𝖯⎯⎯⎯P¯ on ciphertext 𝖢𝖳CT is proportional to the run-time of its clear-form counterpart (program 𝖯P on memory 𝖣D ) up to a polylogarithmic factor in the size of 𝖣D , and we envision tokens that are capable to update the ciphertext, over which other tokens can be subsequently executed. We define a security notion for our primitive and propose a candidate construction from obfuscation, which serves as a starting point towards the realization of other schemes and contributes to the study on how to compute RAM programs over public-key encrypted data.
[University of Luxembourg > Interdisciplinary Centre for Security, Reliability and Trust (SNT) > >]
