Future predicate encryption schemes

[rheitjoh]

(This issue has been imported from the Gitlab repository because it seems to not have been addressed yet)

Original Text (Issue 80)

Currently, we only offer ABE and IBE (and fuzzy IBE) in our predicate-encryption interfaces.
Let's put our APIs to good use and expand this. I propose to add (some of) the following scheme types to our library:

• Hierarchical identity-based encryption (kInd and cInd are sequences of something, predicate is prefix).
• http://eprint.iacr.org/2009/385.pdf (todo: ask Gennadij whether this is THE state-of-the-art construction)
• Broadcast encryption (kInd is an identity, cInd is a set of identities, predicate is inclusion).
• https://eprint.iacr.org/2012/216.pdf (todo: ask Gennadij whether this is THE state-of-the-art construction)

What may also be interesting to add is:

• Some dynamically secure ABE (all our currently implemented constructions are only selectively secure). -> Lewko.
• PE for finite automata. (probably somewhat more work, but cool).