  Several research projects have shown that Byzantine fault tolerance (BFT) is
practical today in terms of performance. Deficiencies in other aspects might
still be an obstacle to a more wide-spread deployment in real-world
applications. One of these aspects is an over-all security architecture beyond
the low-level protocol. This paper proposes the security architecture
SecureSMART, which provides dynamic key distribution, internal and external
integrity and confidentiality measures, as well as mechanisms for availability
and access control. For this purpose, it implements security mechanism among
clients, nodes and an external trust center.
