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Stealthencrypt.com Quick Take: Artists: This article may help you to protect your creative works.
Computer Artists Alert: How Digital Watermarks are Easily Defeated
If you are a computer artist with a growing portfolio, you face increasing risk of theft of your intellectual property, especially if you distribute your work on the internet or on CD-rom. At highest risk for theft are images which can easily be resold as is, slightly altered and resold, or downloaded and posted in "for free" public domain image archives. This latter event could affect your livelihood and render your portfolio nearly worthless if your images are not protected with identifying information.
There are several technical methods for protecting digital artwork.
- The most common protection method is to embed identifying information in the headers of a file. Unfortunately, art thieves can resave the file as another file format, or just copy the file to a file which does not contain any header information, or perhaps the new header even contains their own copyright info.
- Another method is to overlay a transparent watermark onto your image. It is consciously applied in a nearly transparent layer, using an image tool such as Paint Shop Pro 5.0. Art thieves may be able to deconstruct the image and separate the layers to remove your watermark. It is a painstaking process, but it happens to images which are valuable for resale.
- A higher tech method employs expensive digital watermarking applications. Most of them work by encoding copyright data as invisible patterns on the image. Unfortunately, a lot of them are not as fail-safe as their makers claim.
HOW ARE WATERMARKS DEFEATED?
StirMark is a freely available software in the public domain. It was designed to test the strength of watermarks. StirMark's maker says their software will automatically alter watermarks created by Digimarc, SysCoP, JK_PGS, TALISMAN project - EPFL algorithm, Signum Technologies and EIKONAmark. Watermarking researcher Fabian Petitcolas even cracked a PIN # for PictureMarc 1.51, he says "in less than 2 minutes."
The StirMark maker stated that "this proves that these schemes are not robust enough and hence the current technology is not ready for public use. The end result is that StirMark removes digital signatures without altering the appearance of the images."
If you want to test your digital watermarking software with your own images to see if the digital watermarks are defeatable by Stirmark, you can download Stirmark. More information is available here and there is also a paper, Attacks on Copyright Marking Systems.
Another de-watermarking application called unZign works with .jpg format only. unZign is freely available for Windows 95 , but visit altern.org first to read their documentation. The makers says unZign works on watermarked images and is used to test robustness of watermarking software. (It could also be used by digital art thieves.)
Digimarc watermarks were defeated by unZign, as documented at the altern.org site. Altern.org also documented the failure of PGS (Pretty Good Signature), SysCoP, and SureSign (Signum Technologies) digital watermarking systems when unZign was used to test the robustness of the watermarking.
Another method employed by digital art thieves is called "mosaic" where an image is chopped into smaller pieces and reassembled on a web site, using a table without spacing or borders. The image looks the same as if it was uploaded as a whole image.
Other art thieves use resampling, resizing, or resaving in another image format to attempt to defeat digital watermarking.
Conclusion?
Most digital watermarking systems are easy to defeat, either with or without special software de-watermarking tools.
IF NOT DIGITAL WATERMARKING SOFTWARE, WHAT IS THE BEST WAY TO PROTECT MY IMAGES?
Stealthencrypt.com thinks the combination of encryption and steganography makes for a good solution to anti-watermarking programs like unZign and StirMark. Because Stealth Encryption software uses your secret key to encrypt and hide a data file inside your image invisibly, it is much safer than digital watermarking software systems. At the present time, Stealth Encryption works by hiding any type of data file inside either a .bmp or a .tif, so it would be most useful to desktop publishers who commonly use these image formats. We are working on making the program compatible with other image formats, such as .gif and .jpg, and will keep this web site up to date on any enhancements to Stealth Encryption software.
Note: When using Stealth Encryption software to encrypt your intellectual property information info images, we suggest you do not use the same password for every image you create. Though the encryption is safe because of 128-bit strong encryption, a human error on the part of the user, such as writing down the password on a piece of paper and having it stolen, would be like having the same PIN for all of your bank accounts. If you use different passwords for each image, you could store them in the Stealth Encryption Password database.
To read about a digital artist who says hundreds of her images were stolen and are being avidly marketed on CD-rom by another company, click here.