The research should emphasise the critical perspective of RSA cryptographic protocol as an instrument in HR information security, especially taking into consideration payroll records, personal information, and communications. A performance evaluation of RSA based on different key sizes (1024-bit, 2048-bit, and 4096-bit) done in this study established that a balance between security and efficiency in HR systems could be achieved with a 2048-bit size. However, considering the limitation of RSA in the case of large datasets, it comes up with a hybrid encryption model that combines RSA and AES to enhance performance while maintaining maximum security strength significantly. Another developing threat this study addresses is quantum computing and advocates for a shift in solutions by going post-quantum to ensure future-proofing HR systems. Generally, the study leads to practical findings that will secure the HR information systems against not only the threats of today but also the threats of tomorrow.