Since Peris-Lopez et al. proposed the design of ultralightweight authentication schemes [35–37] for low-cost RFID tags in 2006, research community has demonstrated a significant advancement on this interesting research area in recent years. However, previously published studies are subject to either various security vulnerabilities or inefficient management on tag memory. Motivated by the nature of resource limitation in a tag, we develop a process-oriented ultralightweight RFID authentication protocol which delivers strong security intensity, robust privacy protection as well as less tag memory space required. In addition, a randomness evaluation on the output values of our scheme is performed to ensure the proposed authentication protocol produces qualified output randomness. Our security analysis and performance comparison show that our process-oriented authentication scheme outperforms relevant works by supporting essential system security criteria with less computation effort and better tag memory utilization.