This paper presents a comparative analysis of the DRACO stream cipher implemented in both C++ and Rust across three microcontroller platforms: ESP32, ESP8266, and Raspberry Pi Pico. DRACO, a lightweight cipher designed for constrained environments, was evaluated in terms of performance, memory efficiency, and initialization behavior. To ensure reliable and repeatable results, a standardized benchmarking framework was developed, including automated testing, key/IV configuration variants, and statistical analysis of execution times. In addition to synthetic benchmarks, the evaluation incorporated representative smart city data sets, simulating real-world sensor inputs to reflect practical encryption workloads. Performance metrics—including keystream generation, encryption, and algorithm initialization—were collected via serial output and processed using Python and visualization tools.</p> <p>Results show that both implementations perform consistently across varying keystream lengths, with Rust demonstrating faster execution at very short lengths, and C++ slightly outperforming Rust at longer lengths. The study also discusses the implementation challenges and trade-offs between security, compiler support, and platform compatibility. Findings highlight that both languages are suitable for embedded cryptographic applications, with Rust offering stronger language safety guarantees and C++ providing broader microcontroller support. This work further emphasizes the importance of lightweight encryption in smart city sensor networks, where securing real-time, sensitive data is critical to privacy, reliability, and urban infrastructure resilience.