  Individuals and organizations tend to migrate their data to clouds,
especially in a DataBase as a Service (DBaaS) pattern. The major obstacle is
the conflict between secrecy and utilization of the relational database to be
outsourced. We address this obstacle with a Transparent DataBase (T-DB) system
strictly following the unmodified DBaaS framework. A database owner outsources
an encrypted database to a cloud platform, needing only to store the secret
keys for encryption and an empty table header for the database; the database
users can make almost all types of queries on the encrypted database as usual;
and the cloud can process ciphertext queries as if the database were not
encrypted. Experimentations in realistic cloud environments demonstrate that
T-DB has perfect query answer precision and outstanding performance.
