عنوان

Steganography-based secret and reliable communications :

Number

TLets529074

Title Proper

Steganography-based secret and reliable communications :

General Material Designation

[Thesis]

First Statement of Responsibility

Almohammad, Adel

Title Proper by Another Author

improving steganographic capacity and imperceptibility

Subsequent Statement of Responsibility

Ghinea, G. ; Hierons, R. M.

Name of Publisher, Distributor, etc.

Brunel University

Date of Publication, Distribution, etc.

2010

Dissertation or thesis details and type of degree

Thesis (Ph.D.)

Text preceding or following the note

2010

Text of Note

Unlike encryption, steganography hides the very existence of secret information rather than hiding its meaning only. Image based steganography is the most common system used since digital images are widely used over the Internet and Web. However, the capacity is mostly limited and restricted by the size of cover images. In addition, there is a tradeoff between both steganographic capacity and stego image quality. Therefore, increasing steganographic capacity and enhancing stego image quality are still challenges, and this is exactly our research main aim. Related to this, we also investigate hiding secret information in communication protocols, namely Simple Object Access Protocol (SOAP) message, rather than in conventional digital files. To get a high steganographic capacity, two novel steganography methods were proposed. The first method was based on using 16x16 non-overlapping blocks and quantisation table for Joint Photographic Experts Group (JPEG) compression instead of 8x8. Then, the quality of JPEG stego images was enhanced by using optimised quantisation tables instead of the default tables. The second method, the hybrid method, was based on using optimised quantisation tables and two hiding techniques: JSteg along with our first proposed method. To increase the steganographic capacity, the impact of hiding data within image chrominance was investigated and explained. Since peak signal-to-noise ratio (PSNR) is extensively used as a quality measure of stego images, the reliability of PSNR for stego images was also evaluated in the work described in this thesis. Finally, to eliminate any detectable traces that traditional steganography may leave in stego files, a novel and undetectable steganography method based on SOAP messages was proposed. All methods proposed have been empirically validated as to indicate their utility and value. The results revealed that our methods and suggestions improved the main aspects of image steganography. Nevertheless, PSNR was found not to be a reliable quality evaluation measure to be used with stego image. On the other hand, information hiding in SOAP messages represented a distinctive way for undetectable and secret communication.

Information hiding ; Information security ; Watermarking ; Soap steganography ; JPEG coding

Almohammad, Adel

Ghinea, G. ; Hierons, R. M.

Brunel University

Electronic name

p

[Thesis]

276903

a

Y