Development of Efficient Image Steganography System for 3D Image Models

Abstract

Secure communication between two parties present at geographically different locations has become a matter of deep concern with information and technology progressing at such a fast pace. Steganography is the science of hiding secret message inside a harmless looking file in such a way that its presence is unnoticeable by human eye. Secret message to be hidden is considered a stream of binary bits. Secret message is sent by hiding it invisibly inside an innocuous-looking cover media. When the secret message is hidden in the cover file, stego-file is obtained as a result of embedding of secret message. A typical steganography system has two phases-embedding at message-sender side and extraction at message-receiver side. Extraction is termed as blind if cover file is not required for extraction of secret bits from stego-file. A steganography algorithm is called reversible if after extraction of secret message bits, original cover file is obtained. What cryptanalysis is to cryptography, steganalysis is to steganography. Thus, steganography should be done in such a manner that it remains an onerous task for steganalysts. In 3D image steganography system, 3D mesh model is taken as the cover file and a binary stream of secret bits is hidden inside it. A 3D mesh model consists of vertices which join together to form edges. The edges enclose an area called face and these faces make surfaces. Vertices location is the secret bits hiding place in 3D image steganography. Reversible steganography having a blind extraction is a desirable feature. Also, rotation, scaling and translation of a 3D mesh model can be carried out by intruders which can destroy the hidden secret bits. Thus, it is important for a 3D steganography algorithm to safeguard the secret bits from these operations/attacks. In this thesis, a mesh traversal algorithm is proposed. It is based on BFS (Breadth First Search) algorithm.