Indistinguishability Obfuscation Without Maps: Attacks and Fixes for Noisy Linear FE

2020 ◽  
pp. 110-140 ◽  
Author(s):  
Shweta Agrawal ◽  
Alice Pellet-Mary
Keyword(s):  
Indistinguishability Obfuscation

scholarly journals Practical CCA-Secure Functional Encryptions for Deterministic Functions

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Huige Wang ◽  
Kefei Chen ◽  
Tianyu Pan ◽  
Yunlei Zhao
Keyword(s):  
Affirmative Answer ◽  
Inner Product ◽  
Secret Key ◽  
Functional Encryption ◽  
Fine Grained ◽  
Indistinguishability Obfuscation ◽  
Simulation Based ◽  
Multilinear Maps ◽  
Hard Problems ◽  
Generic Transformation

Functional encryption (FE) can implement fine-grained control to encrypted plaintext via permitting users to compute only some specified functions on the encrypted plaintext using private keys with respect to those functions. Recently, many FEs were put forward; nonetheless, most of them cannot resist chosen-ciphertext attacks (CCAs), especially for those in the secret-key settings. This changed with the work, i.e., a generic transformation of public-key functional encryption (PK-FE) from chosen-plaintext (CPA) to chosen-ciphertext (CCA), where the underlying schemes are required to have some special properties such as restricted delegation or verifiability features. However, examples for such underlying schemes with these features have not been found so far. Later, a CCA-secure functional encryption from projective hash functions was proposed, but their scheme only applies to inner product functions. To construct such a scheme, some nontrivial techniques will be needed. Our key contribution in this work is to propose CCA-secure functional encryptions in the PKE and SK environment, respectively. In the existing generic transformation from (adaptively) simulation-based CPA- (SIM-CPA-) secure ones for deterministic functions to (adaptively) simulation-based CCA- (SIM-CCA-) secure ones for randomized functions, whether the schemes were directly applied to CCA settings for deterministic functions is not implied. We give an affirmative answer and derive a SIM-CCA-secure scheme for deterministic functions by making some modifications on it. Again, based on this derived scheme, we also propose an (adaptively) indistinguishable CCA- (IND-CCA-) secure SK-FE for deterministic functions. The final results show that our scheme can be instantiated under both nonstandard assumptions (e.g., hard problems on multilinear maps and indistinguishability obfuscation (IO)) and under standard assumptions (e.g., DDH, RSA, LWE, and LPN).

Proxy re-encryption via indistinguishability obfuscation

2016 ◽  
Vol 9 (12) ◽  
pp. 1786-1795 ◽  
Author(s):  
Satsuya Ohata ◽  
Kanta Matsuura
Keyword(s):  
Indistinguishability Obfuscation
Sign in / Sign up

Export Citation Format

Share Document