DESIGN & EVOLUTION OF A STEGANOGRAPHY SYSTEM FOR SPEECH SIGNAL BY SLANTLET TRANSFOR

Abstract

In this paper a Stegan graphic system was proposed to hide up a secret speech signal in a cover speech signal, using Slant let transform. The combination of a Stegan graphy and cryptography is used to increase the level of security and to make the system more rigid and complex to be defeated by attackers. In cryptography the secret speech signal is converted from 1-D to 2-D signal, divided into blocks each of size (8*8) sampled and then the samples are converted to the binary form, after that, columns transposition is applied to get the ciphered signal. This cipher signal will be the next stage, we are driving the key which is used in cyphering process from the slantlet coefficients.

       The proposed system increases the imperceptibility property because it is based on replacing each secret  bit with one of the host coefficient bit (the host coefficient may be the same as secret bit). So that changing of host signal due to embedding process was decrease d but the dimension of the cover signal will be a tradeoff between the imperceptibility

and the capacity of the system. Imperceptibility and security test s are implemented to check the system. Peak signal to Noise Ratio(PSNR) & Correlation(Corr.) between cover signal & the stego - signal are carried out to evaluate the perform ance of the proposed algorithm