Two Out of Three Threshold Visual Cryptography Data Hiding Scheme for Block Truncation Coding

For Image processing with low computational complexity Block truncation coding (BTC) is an efficient compression tool. However, it has some deficiencies like the blocking and false contour which may cause defective image reproduction. These defects may be improved with the use of error-diffused BTC but the security issues can limit its industrial application. To improve the security issue and to widen the scope of market application, a new method of embedding a secret binary data in the Block Truncation Coded image shares is presented in this paper. The proposed scheme implements two of three threshold visual encryption. Error reduction is achieved by Floyd-Steinberg Error diffusion. The data hiding and recovery involves simple XOR operation which is a low complexity operation. In this scheme, the size of the shares is same as that of the original image. There is no expansion in the share size. The technique can be used with or without Error Diffusion. Keywords—Block Truncation Coding, Error Diffusion, Secret Sharing, Threshold Visual Cryptography.