Reversible AMBTC-based secret sharing scheme with abilities of two decryptions

• We report a reversible secret sharing scheme from stego shadows to their original covers.
• The generated AMBTC-compressed shadows are meaningful.
• The meaningful shadows maintain the same image quality as their original covers.
• There are two ways to recover the secret, stacking and complete decryptions.
• The stego-compressed codes can be decoded by the normal decoding procedure.

This paper presents a secret sharing scheme to encode a secret binary image in images which are compressed by absolute moment block truncation coding (AMBTC) method. The generated shadows by the proposed scheme are in AMBTC-compressed format and meaningful, the visual quality of which is the same as that of its original AMBTC version. In the proposed scheme, the secret image can be reconstructed in two situations: (1) if some light-weight computational devices are available, the secret image can be completely decrypted without any distortion, and (2) otherwise, the secret image can also be revealed by human visual system. Furthermore, the proposed scheme provides the reversibility for protecting the valuable cover images. In addition, underlying the proposed (2,2)(2,2) scheme, this paper gives a construction for the (2,n)(2,n) scheme where one participant may require more than one shadow. Theoretical analysis and simulation results demonstrate the superiority of the proposed scheme.