RE: [WM]: one basic question for fragile watermarking

[Eugene Kurbatov <e_kurbatov@yahoo.com>]

Hello,
  
  Maybe the following publication about reversible scheme for authentication will be useful for you:
  Moon  Ho Lee, Valery Korzhik, Guillermo Morales-Luna, Sergei Lusse, Evgeny  Kurbatov "Image Authentication Based on Modular
Embedding", IEICE TRANSACTIONS on Information and Systems, 2006.
  You can find it under the link:
  http://search.ieice.org/bin/author.php?a_name=Evgeny%20KURBATOV&category=D&year=2006&lang=E
  
  Best regards, Evgeny Kurbatov.
    

 

  
Zou Dekun <dekun.zou@Thomson.net> wrote:  
Zhao,

Two approaches can solve the problem.
1. When extract "hash" bits, use a subset of the host image. When embedding, use those values not selected for hashing.
2. Use reversible watermarking scheme. At the detection stage, the original host image can be recovered.


Best regards,
Dekun

-----Original Message-----
From: watermarking-owner@watermarkingworld.org
[mailto:watermarking-owner@watermarkingworld.org] On Behalf Of Zhao Stephen
Sent: Tuesday, April 11, 2006 1:55 AM
To: watermarking@watermarkingworld.org
Subject: [WM]: one basic question for fragile watermarking

Dear all,
Recently I surveyed some paper on "fragile watermarking" for authentication application.  In these paper, a general scheme is to
first  extract a fingerprinting from host image such as "hash", embed the  "hash" bits into the host image by watermarking method.
In detection phase, the "hash" bits are re-extracted from the watermarked image for final authentication.
I  am puzzled by one question: the extracted "hash" are really identical  before and after the "hash" is watermarked into the host
image, considering watermarking tech is performed by modifying the host image.
Maybe it is contradicting.

Thanks
                            Zhao


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