Abstract
<jats:p>Traditional optical image encryption methods usually produce completely noise-like ciphertexts for high security, but the lack of perceptible ciphertext content before decryption limits their practical application in cloud storage and multimedia communication. We propose a simultaneous image compressive encryption and thumbnail preview based on ghost imaging, which generates ciphertext with preview capability while concealing critical details. During the encryption process, a set of pseudorandom masks, generated by a chaotic system, perform local convolutional sampling on the plaintext image. This low-dimensional measurement, used as the ciphertext, preserves the global contour and low-frequency structural features of the original image by adjusting the sampling stride and convolution kernel size. The legitimate receiver decodes the original image from the ciphertext using the correct key and a compressive sensing algorithm. Experimental results demonstrate satisfactory reconstruction quality under different sampling parameter settings, verifying the scheme’s effective balance between encryption security and visual usability.</jats:p>