Digital image have become the main source of human information acquisition and exchange, which is widely used in aerospace, biomedical and military fields. Therefore, to ensure the secure transmission of digital image, this paper proposes a secure spatio-temporal chaotic pseudorandom generator for image encryption is proposed. Firstly, we consider the potential impact of precision loss in digital circuits on the degradation of chaotic systems. Therefore, we employ the unscented Kalman filter (UKF) to assess accuracy loss in both Logistic, Sine and Chebyshev maps, which is compensated for by introducing perturbations into the spatio-temporal chaotic system. Secondly, we design new Sine maps and Chebyshev maps with time-varying delays to perturb the time dimension of the non-adjacent coupled lattice and improve the complexity and security of the chaotic system. In the end, we use the newly designed spatio-temporal chaotic system as a pseudo-random generator to design a new image encryption scheme. In this paper, we present a security proof for the newly proposed spatio-temporal chaotic system and image encryption scheme. Furthermore, security experiments demonstrate that the spatiotemporal chaotic system and image encryption scheme presented in this paper exhibit improved uniform distribution, absence of chaos degradation or predictability issues while offering randomness suitable for engineering applications.

In this study, a novel reversible data hiding (RDH) in encrypted domain scheme for coding channel based on sliding‐block segmentation and adaptive steganography is proposed. The proposed scheme enriches the residual information with as little additional encryption information as possible to improve the testing error rate of a steganalyser by sliding‐block segmentation with bit stream encryption. The specific encryption process effectively weakens the correlation between the adjacent pixels and minimises the size of key stream bits. The encryption key can be further embedded in the channel code stream before transmitted in the channel. Experimental analysis shows that the image encrypted by the proposed RDH scheme can achieve a peak‐signal‐to‐noise ratio of >50 dB, as the payload is 0.5 bits per pixel (bpp). In terms of security performance, compared with the state‐of‐the‐art methods, their method has a higher testing error rate when the steganalyser is utilised. Even if the payload is 0.5 bpp, the testing error rate is >0.25.