Add paper on definitions of Functional Encryption. Predicate Encryption seems to be a subclass of Functional Encryption.

FossilOrigin-Name: be5579f3832328c1fcdcd51069f355d6726cdeb7d4beae31135d7a41bd641c9b

Author: danshearer

references/lumosql-abe.bib

@@ -260,3 +260,27 @@ @ARTICLE{Herranz2017-ze
   language  = "en"
 }
 
+@misc{cryptoeprint:2010/543,
+      author = {Dan Boneh and Amit Sahai and Brent Waters},
+      title = {Functional Encryption: Definitions and Challenges},
+      abstract = {We initiate the formal study of functional encryption by
+      giving precise definitions of the concept and its security. Roughly speaking,
+      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. For example, given an encrypted program the secret key may enable the
+      key holder to learn the output of the program on a specific input without
+      learning anything else about the program.
+      We show that defining security for functional encryption is non-trivial. First,
+      we show that a natural game-based definition is inadequate for some
+      functionalities. We then present a natural simulation-based definition and show
+      that it (provably) cannot be satisfied in the standard model, but can be
+      satisfied in the random oracle model. We show how to map many existing concepts
+      to our formalization of functional encryption and conclude with several
+      interesting open problems in this young area.},
+      howpublished = {Cryptology ePrint Archive, Paper 2010/543},
+      year = {2010},
+      note = {\url{https://eprint.iacr.org/2010/543}},
+      doi  = {https://doi.org/10.1007/978-3-642-19571-6_16},
+      url = {https://eprint.iacr.org/2010/543}
+}
+