imported>Belbury: Adding short description: "Computer security exploit"

2025-01-22T15:03:16Z

Adding short description: "Computer security exploit"

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{{Short description|Computer security exploit}}
{{distinguish|Replay attack}}

The '''copy attack''' is an attack on certain [[digital watermarking]] systems proposed by M. Kutter, S. Voloshynovskiy, and A. Herrige in a paper presented in January, 2000 at the Photonics West [[SPIE]] convention.<ref>M. Kutter, S. Voloshynovskiy, and A. Herrigel. The Watermark Copy Attack. Proceedings of the SPIE, Security and Watermarking of Multimedia Contents II, Volume 3971, pages 371-379. San Jose, CA, 2000.</ref>

In some scenarios, a digital watermark is added to a piece of [[Computer media|media]] such as an [[image]], [[film]], or [[audio clip]], to prove its authenticity. If a piece of media were presented and found to lack a watermark, it would be considered suspect. Alternatively, a security system could be devised which would limit a user's ability to manipulate any piece of media which contained a watermark. For instance, a [[DVD burner]] may prohibit making copies of a film which contained a watermark.

The copy attack attempts to thwart the effectiveness of such systems by estimating the watermark given in an originally watermarked piece of media, and then adding that watermark to an un-watermarked piece.<ref>{{Cite journal|last1=Deguillaume|first1=F.|last2=Voloshynovskiy|first2=S.|last3=Pun|first3=T.|date=2003-10-01|title=Secure hybrid robust watermarking resistant against tampering and copy attack|url=https://linkinghub.elsevier.com/retrieve/pii/S0165168403001725|journal=Signal Processing|language=en|volume=83|issue=10|pages=2133–2170|doi=10.1016/S0165-1684(03)00172-5|bibcode=2003SigPr..83.2133D |s2cid=17092667 }}</ref> In the first scenario listed above, this would allow an attacker to have an inauthentic image declared authentic, since it contains a watermark. In the second scenario, an attacker could flood the market with content which ordinarily would allow a user to manipulate it as he saw fit, but due to the presence of the watermark, limitations would be imposed. In this way, schemes which sought to limit use of watermarked media may prove to be too unpopular for wide distribution.

In a 2003 paper presented at the [[International Conference on Acoustics, Speech, and Signal Processing]],<ref>J. Barr, B. Bradley, and B. Hannigan. [https://www.digimarc.com/docs/default-source/technology-resources/published-technical-papers/commercial-applications/dmrc_image_signatures.pdf Using Digital Watermarks with Image Signatures to Mitigate the Threat of the Copy Attack]. Proceedings of ICASSP, 2003</ref> John Barr, Brett Bradley, and Brett T. Hannigan of [[Digimarc]] describe a way to tie the content of the digital watermark to the underlying image, so that if the watermark were placed into a different image, the [[watermark detection]] system would not authenticate it.

==References==
{{reflist}}

[[Category:Computer security exploits]]
[[Category:Watermarking]]

Copy attack - Revision history

imported>Belbury: Adding short description: "Computer security exploit"