FIFE : a Framework for Investigating Functional Encryption

Abstract

In functional encryption, keys are associated with functions, and ciphertexts with messages. Decrypting a message with a key gives the evaluation of the associated function on that message. We look at bounded-collusion functional encryption, where the number of keys for which security is guaranteed is bounded, as it is possible to realize using standard building blocks. For such schemes we aim to understand their practicality for real-world applications. There are some theoretical constructions of functional encryption, but few implementations. We rectify this by creating the Framework for Investigating Functional Encryption (FIFE). FIFE includes the first implementations for Sahai and Seyalioglu's one-key scheme (CCS 2010), and Gorbunov, Vaikuntanathan, and Wee's bounded-collusion scheme (CRYPTO 2012), and is easily extendable. We used FIFE to evaluate their performance, and to measure the impact of using different public-key or secret-key encryption schemes, bounds on collusion, and security levels, for interesting classes of functions.