Combining Semi-Tensor Product Compressed Sensing and Session Keys for Low-Cost Encryption of Batch Information in WBANs

In the previous encryption schemes for sensor information security in WBANs, there are usually the disadvantages of high cost and low time efficiency. At the same time, a large amount of information flooding into the channel also tends to bring huge transmission pressure to the channel. Motivated by the above viewpoints, a scheme that combines semi-tensor product compressed sensing (STP-CS) and session keys (SesKs) for low-cost batch information encryption in WBANs is proposed using image information as an example. The STP-CS can not only compress the information under the guarantee of high reconstruction quality, which reduces the pressure on the channel to transmit the information but also solves the problem of weak compatibility of traditional compressed sensing (CS) on the image size. The SesKs obtained by the communicating parties through the negotiation of the secret keys (SKs) cannot be returned to the SKs for a limited period of time. The cost of achieving one-time pad encryption is also lower compared to the traditional stream cipher encryption, which improves the robustness of wireless broadband network transmission. In terms of the encryption algorithms, the batch image encryption algorithms ensure the timeliness of information transmission security. The results show that the key space of the scheme is as high as 2869, the reconstructed image of $256\times 256$ under compression ratio of 0.75 can still obtain PSNR as high as 45.94 dB, and the information entropy of the encrypted image is as high as 7.9978. Compared with the other encryption schemes, the scheme is more suitable to be applied to WBANs because it ensures sufficient security while having the features of low cost, high compatibility, and high efficiency.