  Outsourcing data in the cloud has become nowadays very common. Since --
generally speaking -- cloud data storage and management providers cannot be
fully trusted, mechanisms providing the confidentiality of the stored data are
necessary. A possible solution is to encrypt all the data, but -- of course --
this poses serious problems about the effective usefulness of the stored data.
In this work, we propose to apply a well-known attribute-based cryptographic
scheme to cope with the problem of querying encrypted data. We have implemented
the proposed scheme with a real-world, off-the-shelf RDBMS and we provide
several experimental results showing the feasibility of our approach.
