Abstract
Managing network infrastructure resilience under hostile conditions is a fundamental priority for modern smart university ecosystems. This paper introduces an advanced analytical framework to model and quantify the resilience of hybrid networks protected by Shamir Secret Sharing and Diffie-Hellman cryptographic protocols under intelligent targeted cyber-attacks. The network architecture incorporates a primary hybrid path operating under a 4-out-of-5 threshold logic alongside an independent fallback path managed by a backup componentB_6. A rigorous mathematical derivation using probability theory establishes the joint availability equations for both normal operation and targeted strategic strikes, where an attacker specifically aims to compromise vital edge components B_1andB_5. To validate the closed-form reliability expressions, a robust Monte Carlo simulation with 10^5 iterations was executed in MATLAB. The numerical findings demonstrate that while targeted attacks reduce the primary path's capacity to zero, the independent backup mechanism successfully preserves data-flow continuity and encryption integrity, maintaining a steady system availability floor of R_(sys.)≥ 0.90. These insights provide concrete engineering design criteria for implementing fault-tolerant secure data pathways in digital academic institutions.