Abstract:

Image sharing usually splits the secret image into a series ofshadow images and the secret image can be completely recovered by partial or all distributed shadow images. It is the research hotspot in image security. But traditional image sharing usually used to construct the secret imagecompletely and the research providingthe whole progressive recovery of secret image from fuzzy to clear is relatively small.Based on this, a multiple thresholds progressive secret image sharing scheme based on DCT was proposed.First the key is shared in combination with the random participation value,the MD5 values corresponding to the sub-keys and participating values are published to prevent participants from cheating,then the secret image is transformed by 8x8 DCT where the DCT coefficients are randomly quantified and the binary representation of the assigned code length distribution table is presented to form multiple partition bands by zigzag scanning order and band reorganization.Finally, use multiple thresholds to sharing the band and reconstruct distribution shadow image in GF(2⁸) Galois field.The experimental results show that when the number of participants is greater than the minimum threshold, withthe number ofparticipant’sincreases, the proposed method can make use of the shadow image to make the whole progressive recovery of secret image from fuzzy to clearand the more participantsand the better visual recovery quality. Otherwise, there will not be any information on the secret image, and the strategy is strictly dependent on the key and the recovery results tend to be stable.

Key words: image sharing, multiple thresholds, progressive sharing, Galois field, DCT