Real-Time Bit-Level Encryption of Full High-Definition Video Without Diffusion
About
Despite the widespread adoption of Shannon's confusion-diffusion architecture in image encryption, the implementation of diffusion to sequentially establish inter-pixel dependencies for attaining plaintext sensitivity constrains algorithmic parallelism, while the execution of multiple rounds of diffusion operations to meet the required sensitivity metrics incurs excessive computational overhead. Consequently, the pursuit of plaintext sensitivity through diffusion operations is the primary factor limiting the computational efficiency and throughput of video encryption algorithms, rendering them inadequate to meet the demands of real-time encryption for high-resolution video. To address the performance limitation, this paper proposes a real-time video encryption protocol based on heterogeneous parallel computing, which incorporates the SHA-256 hashes of original frames as input, employs multiple CPU threads to concurrently generate encryption-related data, and deploys numerous GPU threads to simultaneously encrypt pixels. By leveraging the extreme input sensitivity of the SHA hash, the proposed protocol achieves the required plaintext sensitivity metrics with only a single round of confusion and XOR operations, significantly reducing computational overhead. Furthermore, through eliminating the reliance on diffusion, it realizes the allocation of a dedicated GPU thread for encrypting each pixel within every channel, effectively enhancing algorithm's parallelism. The experimental results demonstrate that our approach not only exhibits superior statistical properties and robust security but also achieving delay-free bit-level encryption for 1920$\times$1080 resolution (full high definition) video at 30 FPS, with an average encryption time of 25.84 ms on a server equipped with an Intel Xeon Gold 6226R CPU and an NVIDIA GeForce RTX 3090 GPU.