Secret Sharing and Information Hiding by Shadow Images

Secret sharing schemes and information hiding schemes have been separately developed by many researchers over years. Some researchers have been integrated information hiding technique into their proposed secret sharing scheme with the purpose of hiding shares and authentication. However, the combination of a secret sharing scheme and an information hiding technique with high embedding capacity is not explored by researchers. This paper presents a new secret sharing and information hiding scheme by grayscale images. The proposed scheme embeds a secret image and a secret bit stream into two shadow images. The experimental results show that the proposed scheme achieves very high embedding capacity (i.e. about 3 bits per pixel). Furthermore, after the secret bit stream has been extracted, the secret image can be completely restored pixel by pixel.