A reversible and authenticable secret sharing scheme using dual images

Reversible data hiding (RDH) is a steganographic method that can restore the cover medium after extracting the embedded secret data. This work proposes a novel RDH scheme based on turtle shell (TS) reference matrix with dual image shadows. By modifying a cover pixel pair, two stego pixel pairs are generated and separately recorded to two image shadows. The first stego pixel pair is embedded with three bits of secret data, while the second stego pixel pair is embedded with one secret bit and require no information for recovery of the cover pixels. Since secret data is embedded through slight modification of cover pixel values, experimental results show that the image shadows have good visual quality and are robust under steganalysis attack. In addition, an authentication mechanism is proposed to detect tampered shadows.