Hiding Information in Vector Layer While Extracting Layers from Raster Data
Vinay Kumar, Abhishek Bansal, Sunil Kumar Muttoo · Information Security Journal A Global Perspective · 2012
A topographic sheet contains information about road, rail, river, etc., of a particular geographical area. This information is used as a channel for hiding secret messages in a layer that is extracted from the topographic sheet through digitization in vector map form. The extraction of layers is carried out either manually or semi-automatically. Manual extraction is done either through tablet or through a process called onscreen digitizing. The onscreen digitizing is used here to hide message simultaneously with the extraction of the vector layer. A message is string of bits. Bit ‘1’ and ‘0’ of a message are coded as node and intermediate point, respectively, in the vector layer. A digital vector map is generated using three basic components: node, intermediate point, and segment. Three tolerance values of dangle, fuzzy, and weed determine the closeness of two nodes and two intermediates point in a segment. An algorithm is developed to hide/extract information in vector map form of a topographic sheet. The process is very useful for sharing contextual intelligence.