This paper presents an analysis of the security performance and evaluation of the hardware architecture of the redundant bit security (RBS) cryptosystem. RBS is a lightweight symmetric encryption algorithm that targets resource-constrained RFID devices. Unlike the existing cryptosystems, RBS simultaneously provides confidentiality, authentication, and integrity of the plaintext by inserting hash-generated redundant bits among the already modified plaintext data. A flexible-length hash algorithm in our optimized hardware architecture allows RBS to support different key sizes which allows flexibility in the security level. Our analysis shows the resilience of RBS against powerful and well-known attacks such as differential attacks and known-plaintext attacks. We compare the performance of the RBS cryptosystem against other distinguished ciphers developed for RFID systems. Simulation results show that RBS results in approximately 100%, 239%, and 153% higher hardware efficiencies while requiring 48%, 56%, and 59% less energy-per-bit compared to H-PRESENT, HB-2, and Grain, respectively. Such results present confirmatory evidence that RBS is a superior solution for providing security in resource-constrained systems such as RFID systems especially when authentication is a priority.