Hybrid and Blind Steganographic Method for Digital Images Based on DWT and Chaotic Map

Abstract

Steganography is the art and science of hiding secret information into digital media with the intention to transmit this information. Most of the steganographic methods either use spatial domain or frequency domain for embedding the secret information. Current hybrid methods require the original cover image to extract the secret information making these methods to become not practical. This paper proposes a new blind steganographic method for digital images that combines spatial and frequency domains and does not rely on the cover image in extracting the secret information. The proposed method utilizes a chaotic map to scramble the secret information before the embedding procedure takes place. A coding map is generated during the work on spatial domain, and the original image is transformed into DWT domain, then the generated coding map is embedded in the coefficients of LL and HL sub-bands of the cover image. The drawn experimental results show that the resultant stego-images have high quality and the proposed method provides high embedding capacity compared with other methods and is robust against the visual analysis and other image processing attacks such as lossy compression and added noise. 