A DWT Based Approach for Image Steganography

Abstract

In this paper we propose a new steganography technique which embeds the secret messages in frequency domain. According to different users' demands on the embedding capa c- ity and image quality, the proposed algorithm is divided into two modes and 5 cases. Unlike the space domain approaches, secret messages are embedded in the high frequency coefficients re- sulted from Discrete Wavelet Transform. Coefficients in the low frequency sub-band are pre- served unaltered to improve the image quality. Some basic mathematical operations are per- formed on the secret messages before embedding. These operations and a well-designed map- ping Table keep the messages away from stealing, destroying from unintended users on the inter- net and hence provide satisfactory security.