I think tackling the multi-faceted problem of securing the database and the
client-server communications would be a fine thesis topic. Do the necessary
research/discussions to determine the best approach to securing a database
from unwelcome inspection. Implement it in Firebird. Also securing the
communication between client and server.

Much discussion has already taken place. Many details and alternatives need
to be examined and then rejected for various reasons. Work done in other
projects needs to be found and examined to see if Firebird can make use of
their best practices.