Manufacturing companies aim for the optimization of their processes by means of Computer Integrated Manufacturing (CIM), in order to keep-up with the competition and the evolution of clients' needs. This transformation is based on connecting the shop floor systems to the high business layer ones. Based on the limitations of the existing architectures in the literature, we proposed the BLAEM architecture (Bi-Level Architecture for Efficient Manufacturing), an ISA95-based architecture that relies on six major aspects, among which we can cite Cybersecurity. In this paper, we focus on this specific aspect, and we try to elaborate a security index to evaluate the implementation of our architecture.