关键词: 图像分存,有意义图像分存,(K,N)门限方案,GF有限域,无扩张

Abstract: There is pixel expansion in conventional meaningful image sharing schemes which usually use short authentication information to verify the correctness of sharing information and bring defect that the facticity of the reconstructed secret image pixels cannot be accurately identified.To address these problems,a meaningful (K,N) free expansion ima-ge sharing scheme based on GF(2³) was proposed.In the proposed scheme,firstly a key is used to generate an encryption mapping table and then this table and secret image pi-xel location information are used to encrypt secret image pixels.Secondly (K,N)-threshold scheme based on GF(2³) is used to share the ciphered pixels and pixels authentication information and then they are embedded into N cover images.Finally the key which is used to generate encryption mapping table is also shared into N sub-keys by (K,N)-threshold scheme and the sub-keys’ MD5 values are published to the third reliable party to prevent cheating from distributed cover image holders.The experimental results show the proposed scheme can accurately detect attacked regions in reconstructed secret image.By comparing with conventional methods,the proposed scheme does not have any pixel expansion and distributed cover images have better visual quality.

Key words: Image sharing,Meaningful image sharing,(K,N)-threshold scheme,Gloise field,Free expansion