Progressive sharing of multiple images with sensitivity-controlled decoding

Abstract

Secure sharing of digital images is becoming an important issue. Consequently, many schemes for ensuring image sharing security have been proposed. However, existing approaches focus on the sharing of a single image, rather than multiple images. We propose three kinds of sharing methods that progressively reveal n given secret images according to the sensitivity level of each image. Method 1 divides each secret image into n parts and then combines and hides the parts of the images to get n steganographic (stego) JPEG codes of equal importance. Method 2 is similar; however, it allocates different stego JPEG codes of different 'weights' to indicate their strength. Method 3 first applies traditional threshold-sharing to the n secret images, then progressively shares k keys, and finally combines the two sharing results to get n stego JPEG codes. In the recovery phase, various parameters are compared to a pre-specified low/middle/high (L/M/H) threshold and, according to the respective method, determine whether or not secret images are reconstructed and the quality of the images reconstructed. The results of experiments conducted verify the efficacy of our methods.

Secret Image Sharing Revisited: Forbidden Type, Support Type, and Their Two Approaches

“…Because sharing is useful, all four aforementioned papers [1][2][3][4] have been frequently cited, particularly Shamir [1], which has had more than 10,000 citations from 1979 to 2019. Many recent studies have also focused on sharing [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Finally, as for image sharing, some readers may wonder why one cannot just use a key to encrypt the secret image and then share the key with authorized personnel.…”