I'm trying to make my way in Functional Encryption used for access control.
I read a lot of papers such as "How to Run Turing Machines on Encrypted Data", "Functional Encryption: New Perspectives and Lower Bounds", or "Attribute-based encryption for circuits" and I ended up with a feeling of uncertainty in my understanding as they are quite hard to digest. What I'm looking for is an ABE-like scheme where policy may contain both logic and algebraic gates. For example:
"job=doctor" AND "age mod 2 = 0"
this (stupid) policy provides access to the plaintext to doctors whose age is even.
Pushing on the line, a policy could include arbitrary computation such as a signature verification algorithm. From what I read, I feel the only hope of achieving these goals lies in FE. Is there a scheme able to meet these requirements (at least the first policy)? At which cost?
How much of what I wrote is reality, what is achievable and what is fiction?