International Journal of Advanced Research in Computer Science and Software Engineering (IJARCSSE)
For a gray scale document image a new authentication method based on secret sharing technique with data repair capability use of Portable Network Graphics (PNG). For each block of gray scale document image an authentication signals are generated, i.e. together with binarized block content. The shamir secret sharing scheme is used to shares the authentication signals of gray scale document image. Many shares are generated and embedded in to an alpha channel plane then alpha channel plane is combined with original gray scale image to form a PNG image.