A distortion free multi-secret image sharing with efficient shadow communication overhead

Traditional secret image sharing deals with encoding one secret image into two shares. Natural extension of traditional secret image sharing is multiple secret encoding into the same number of shares which reduces the communication and storage overhead. This paper proposes a multiple secret image sharing technique with minimum pixel expansion and share size. In (2, 2) secret image sharing generally two shares of equal size are required to be stored. While in the proposed scheme, one of the shares is replaced with a key which is taking the size of only one row of the share. However minimum bits are required to be 100 for the security reason, so if the bits in key is less than this value, it is made up to this size by padding extra random bits. So now in total, only one share with almost one extra row is needed to be stored resulting in the reduction of communication and storage overhead to almost half. The size of the shares and original secret image is approximately same so the reconstructed secret image will be distortion free. The advantages and its applicability of the propose scheme has been demonstrated by experimental results.