20-09-2014, 09:42 AM
Extracting Spread-Spectrum Hidden
Data from Digital Media
Extracting Spread-Spectrum.doc (Size: 47.5 KB / Downloads: 204)
We consider the problem of extracting blindly data embedded over a wide band in a spectrum (transform) domain of a digital medium (image, audio, video). We develop a novel multicarrier/ signature iterative generalized least-squares (M-IGLS) core procedure to seek unknown data hidden in hosts via multicarrier spread-spectrum embedding. Neither the original host nor the embedding carriers are assumed available. Experimental studies on images show that the developed algorithm can achieve recovery probability of error close to what may be attained with
known embedding carriers and host autocorrelation matrix.
EXISTING SYSTEM
In the existing system reversible data hiding technique the image is compressed and encrypted by using the encryption key and the data to hide is embedded in to the image by using the same encryption key. The user who knows the secret encryption key used can access the image and decrypt it after extracting or removing the data hidden in the image. After extracting the data hidden in the image then only can be the original image is retrieved.
PROPOSED SYSTEM
We propose the information hiding concept to reduce the risk of using cryptographic algorithms alone. Data hiding techniques embed information into another medium making it imperceptible to others, except for those that are meant to receive the hidden information and are aware of it presence. It focuses on methods of hidden data in which cryptographic algorithms are combined with the information hiding techniques to increase the security of transmitted data.
we focus our attention on the blind recovery of secret data hidden
in medium hosts via multi-carrier/signature direct-sequence spread-spectrum transform domain embedding.
Multi-Carrier Spread Spectrum Embedding:
The technique of spread spectrum may allow partly to fulfill the above requirements. Advantages of spread spectrum techniques are widely known: Immunity against multi-path distortion, no need for fiequency planning, high flexibility and variable data rate transmission. The capability of minimising multiple access interference in direct-sequence code- division-multiple-access system is given by the cross-correlation properties of spreading codes. In the case of multi-path propagation the capability of distinguishing one component fiom thers in the composite received signal is offered by the auto-correlation roperties of the spreading codes.
CONCLUSION
We considered the problem of blindly extracting unknown
messages hidden in image hosts via multi-carrier/signature spread-spectrum embedding. Neither the original host nor the embedding carriers are assumed available. We developed a low complexity multi-carrier iterative generalized least-squares (M-IGLS) core algorithm. Experimental studies showed that M-IGLS can achieve probability of error rather close to what may be attained with known embedding signatures and known original host autocorrelation matrix and presents itself as an effective countermeasure to conventional SS data embedding/ hiding5.