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Token-based multi-input functional encryption. (English) Zbl 1421.94036
Baek, Joonsang (ed.) et al., Provable security. 12th international conference, ProvSec 2018, Jeju, South Korea, October 25–28, 2018. Proceedings. Cham: Springer. Lect. Notes Comput. Sci. 11192, 147-164 (2018).
Summary: In this paper, we put forward the notion of a token-based multi-input functional encryption (token-based MIFE) scheme – a notion intended to give encryptors a mechanism to control the decryption of encrypted messages, by extending the encryption and decryption algorithms to additionally use tokens. The basic idea is that a decryptor must hold an appropriate decryption token in addition to his secrete key, to be able to decrypt. This type of scheme can address security concerns potentially arising in applications of functional encryption aimed at addressing the problem of privacy preserving data analysis. We firstly formalize token-based MIFE, and then provide two basic schemes based on an ordinary MIFE scheme and a public key encryption scheme and a pseudorandom function (PRF), respectively. Lastly, we extend the latter construction to allow decryption tokens to be restricted to specified set of encryptions, even if all encryptions have been done using the same encryption token. This is achieved by using a constrained PRF.
For the entire collection see [Zbl 1398.94007].
94A60 Cryptography
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