## 2 Traditional Encryption Techniques
### Impact of Low-Orbit Communication Conditions  
Low Earth Orbit (LEO) communication channels are characterized by high dynamics and a constrained bandwidth, which introduce several challenges that adversely affect the performance of conventional encryption methods.  
UAV movement, physical obstructions, and atmospheric conditions contribute to packet loss and sporadic connectivity. Under LEO conditions, fluctuations in the signal-to-noise ratio (SNR) critically impact the encryption performance. Specifically, AES experiences a rapid degradation in key synchronization and data integrity, while RSA suffers from increased error rates in transmitted ciphertext due to its reliance on stable data channels. Studies indicate that these adverse conditions can reduce the data rate by up to 30% for AES [8,21,22,23,24,25]. Such degradation may delay the transmission of essential information (e.g., wildfire alerts or crop condition data), thereby undermining timely decision-making. Although adaptive error correction mechanisms--such as low-density parity-check (LDPC) codes or real-time retransmission protocols--can mitigate packet loss, they also impose additional computational overhead that may be impractical for resource-constrained UAV systems.  
The considerable distance between UAVs and ground stations inherently increases communication latency. This delay adversely affects the efficiency of encryption and decryption processes, particularly when using asymmetric algorithms like RSA. The propagation delay (D) can be estimated using the following formula: D = d/c, where d represents the distance between the transmitter and receiver, and c is the speed of light. At a typical LEO altitude of 400 km, the delay is approximately 1.3 ms--a critical factor for applications requiring rapid responses. At higher UAV altitudes, the latency increases further, leading to delays in RSA key exchanges and diminishing its suitability for time-sensitive applications such as real-time wildfire monitoring [9,26,27,28,29,26,29,30]. Simulations have shown that RSA-induced delays can exceed 5 ms at elevated altitudes, thereby impairing the operational efficiency.  
The signal transmission conditions in LEO can vary rapidly due to UAV motion, atmospheric fluctuations, and other dynamic factors. While incorporating redundancy mechanisms such as forward error correction can help reduce data loss, these techniques may increase the computational load by up to 15% for AES and 25% for RSA. This increased processing demand further strains UAV systems that already operate under tight resource constraints. Moreover, adverse weather conditions--including rain, snow, and fog--exacerbate packet loss and signal attenuation, resulting in AES encryption rates declining by up to 40% and RSA error rates rising by 15% [31,32]. Such effects further compromise the reliability of traditional encryption methods in UAV operations.  
LEO communication channels inherently offer a limited bandwidth, which can become a bottleneck when transmitting large volumes of encrypted data. This limitation is particularly significant for asymmetric algorithms, which typically produce a larger volume of encrypted data compared to symmetric methods. Figure 1 illustrates the impact of data transmission delay on the execution times of the AES and RSA encryption algorithms.