RE: [WM]: What is different bewteen watermarking and steganography

["Bloom Jeffrey" <Jeffrey.Bloom@thomson.net>]

Huynh Thai Hoc,

You have received a number of different answers.  Dr. Johnson's answer is the most widely accepted.  In watermarking, the payload
carries information about the carrier.  The carrier is the item of primary importance.  This is what motivates the need for
perceptual similarity.
You can't watermark a movie by replacing it with a different movie.  On the other hand, in steganography, the carrier is simply an
unimportant envelope designed to carry the important information.  Here, high fidelity is not required, instead, the marked or stego
work must look "normal" or "typical"; even under statistical study.  For example, it may be OK to introduce visible blocking
artifacts if those artifacts appear indistinguishable from JPEG artifacts.  In steg, you can often pick the cover work from a
desired distribution.

--------------------------------------------------------
Dr. Jeffrey A Bloom, Content Security Research Group Thomson Corporate Research, Princeton, NJ, USA
http://www.geocities.com/Jeffrey_Bloom
(609) 987-7727, (609) 987-7299 fax


> -----Original Message-----
> Sent: Sunday, February 26, 2006 9:12 PM
> Subject: Re: [WM]: What is different bewteen watermarking and
>steganography    The primary difference between watermarking and
>steganography is  implementation and intent of use.
> 
> In short:
> 
> Under Steganography, the embedded message may have nothing to do with
the
> carrier.  The carrier is simply a mechanism to pass the message.  The
> object of the communication channel is the hidden
message.
> 
> Under Watermarking, the embedded information can be considered an
>attribute of the carrier and conveys additional information or
>properties about the carrier.  The primary object of the communication
>channel is the carrier itself.
> 
> --
> 
> Neil
> 
> Neil F. Johnson, Ph.D.
> http://www.jjtc.com
> nfj@jjtc.com
> 
> >    Hi everyone,
> >
> >   I am confusing about the terminology "watermarking" and
> "steganography".
> > Could you help me to classify these terminology. What is different
> > bewteen watermarking and steganography?
> >
> >   I am looking forward to hearing from you.
> >   Thank you very much
> >
> >   Huynh Thai Hoc
> >
> >   University of Technology - HCMC - VietNam


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