Ye Yuan
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Functional Encryption

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Functional Encryption

Functional encryption supports restricted secret keys that enable a key holder to learn a specific function of encrypted data, but learn nothing else about the data.

Functional Encryption Syntax

Definition. A functionality defined over is a function described as a (deterministic) Turing Machine. The set is called the key space and the set is called the plaintext space. We require that the key space contain a special key called the empty key denoted .

Definition. A functional encryption scheme (FE) for a functionality defined over is a tuple of four PPT algorithms (setup, keygen, enc, dec) satisfying the following correctness condition for all and :

  • : generate a public and master secret key pair
  • : generate secret key for
  • : encrypt message
  • : use to compute from

then we require that with probability .

References

[1] @inproceedings{boneh2011functional, title={Functional encryption: Definitions and challenges}, author={Boneh, Dan and Sahai, Amit and Waters, Brent}, booktitle={Theory of Cryptography: 8th Theory of Cryptography Conference, TCC 2011, Providence, RI, USA, March 28-30, 2011. Proceedings 8}, pages={253--273}, year={2011}, organization={Springer} }

[2] https://en.wikipedia.org/wiki/Functional_encryption#