# Energy Consumption Analysis of ISO/IEC 29192-2 Standard Lightweight Ciphers
## 5 Discussion  
When real-time data from the test environment is evaluated, it is clear that the LEA algorithm significantly outperforms other algorithms. The LEA algorithm is based on ARX. As a result, encryption and decryption are limited to basic bit-wise operations. Therefore, energy usage is extremely low. ARX-based encryption algorithms are known to be fast and suitable for IoT systems [36]. Therefore, the LEA algorithm is expected to give good performance. While 1 KB of data is encrypted in the edge device in the test environment, only 32% of the runtime and energy used is spent in AM. The device is switched to LPM for the remainder of the operation. Unlike other ISO/IEC 29192-2 algorithms, CLEFIA shares structural similarities with AES due to its complex computational operations. Notably, the GF multiplication-based diffusion layer based on GF multiplication alone accounts for approximately 52.5% of the total runtime. During both encryption and decryption, the device remained in active mode (AM) throughout the entire process and was unable to transition to low-power mode (LPM), resulting in increased energy consumption. This prolonged active operation makes CLEFIA considerably slower and more energy-intensive compared to other algorithms. For battery-powered IoT devices deployed in the field, such inefficiencies are critical. Optimizing the diffusion layer, which is responsible for the majority of the computational workload, could lead to significant improvements in performance and energy efficiency. When compared to other algorithms, the PRESENT algorithm delivered the worst results. Because of its shorter block length, the PRESENT algorithm has more rounds. At the same time, despite having a simple key schedule stage, the PRESENT algorithm generates round keys while encrypting or decrypting. Other algorithms generate the required keys during the key schedule stage before the start of the round. This could have contributed to PRESENT's poor performance. The PRESENT algorithm was in AM for 85.9% of its runtime, while the remainder of the time, the device was in LPM. Although AES is a widely used robust encryption algorithm, it is not optimized for resource-constrained environments. In such environments, the lightweight encryption algorithms PRESENT, CLEFIA, and LEA offer more energy-efficient solutions than AES. LEA is characterized by the lowest energy consumption and fast runtimes, making it a much more efficient option than AES for IoT devices, where energy savings are critical. CLEFIA performs similarly to AES with lower energy consumption, while at the same time providing lower computational cost. However, PRESENT stands out as a less efficient option than AES in terms of energy consumption due to its high round count and long run times. Overall, AES provides strong security and LEA and CLEFIA offer better energy efficiency and performance, while PRESENT is at an energy disadvantage. Tests can be conducted on other platforms; however, given the structure of encryption algorithms or the computational parts, the results are expected to be broadly similar. Even when different processor architectures or hardware specifications are utilized, variations in energy consumption and performance will remain within comparable ranges. A direct comparison between CLEFIA and LEA across identical key sizes (128, 192, and 256 bits) further reinforces LEA's advantage in terms of both energy efficiency and runtime. At the 128-bit key size, LEA consumed approximately 78.7% less energy and completed the encryption process 76.3% faster than CLEFIA. In the 192-bit configuration, LEA also outperformed CLEFIA, using 30.9% less energy and achieving a 27.9% reduction in runtime. The most significant performance gap was observed at the 256-bit level, where LEA required 69.2% less energy and executed the encryption 69% faster.