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syvaidya / openstego

OpenStego is a steganography application that provides two functionalities: a) Data Hiding: It can hide any data within an image file. b) Watermarking: Watermarking image files with an invisible signature. It can be used to detect unauthorized file copying.
https://www.openstego.com
GNU General Public License v2.0
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Output Stego File as a .JPEG #8

Closed macphoto closed 7 years ago

macphoto commented 8 years ago

Is it possible to output the hidden message file as a .JPEG? The .PNG file format doesn't support metadata fields. Well, not as many fields. .PNG is omitting some of my metadata info and it's critical that the information be found in the file. This issue is throwing off my workflow too.

macphoto commented 8 years ago

Verify Watermark only indicates the strength of the message impression. But can it preview or extract the hidden impression?

syvaidya commented 7 years ago

Unfortunately, answer to both your queries is No.

  1. JPEG is a lossy compression format, and it cannot maintain the embedded message fidelity.
  2. Whenever image with watermark is modified (e.g. crop, resize, etc), the watermark quality degrades. Even simple saving the file as JPEG can cause watermark to degrade. So only thing that software can do is to verify the strength given the original signature. We can output the extracted signature but it might be gibberish.
macphoto commented 7 years ago

Thanks for your reply.

FYI, I've began using Adobe Bridge to implement the meta data code into the .png file format. Adobe Bridge appears to be the only software that will successfully embed meta data into the .png file format.