Image Steganography?

Before I trudge through the depths of coding such a beast, I was wondering if anyone knew of a steganography program that would embed a non-encrypted 1-bit image in the low oder bits of another image. Basically performing a near-imperceptible watermarking of the main image.

I found a lot of programs that will encrypt text or other data into an image, or sound file, but I want the watermark image to remain "visible", therefore it must remain un-encrypted. It must also be spread through the low order bits of the image and not just tacked into the EXIT/IPTC section.
This way if the image is resized, recompressed or otherwise mildly modified, most of the watermark will still be recoverable. (encrypted data would be destroyed and unrecoverable if the image is modified in any way).

Hmmm, maybe someone knows the algorithms better, but as I think about this a bit more...
If an image was embedded in a jpeg and the image was recompressed (resized or cropped for example), I suppose the low order bits would be mostly stripped anyway.

Would this effort end up being pointless?

Say what?

I assume you're wanting to protect images in some way using this technique? I am sure someone somewhere will have either done it or tried and failed!

Mike

The only steganography software I have used in the past is Paranoia - this allows you to use a key image / or key text to encrypt and retrieve hidden text. Not sure how well this holds up after the image has been edited or resized.

I believe it would be a mammoth coding task where expertise in digital cryptography would be essential.

Hope that helps!

There are several commercial watermarking technologies available. Some will watermark the digital image, but you'll lose that when printed. Others will allow even printed (and I've heard even several generation prints) to retain a provable watermark.

However, many of these are pretty expensive and involve subscriptions and the like.

Yes, you could embed something in the low order bits - most likely in the luminance channel of the JPG (rather than the colour), but it'll probably get corrupted when resized or resampled. If it's tough enough to withstand resizing then it's likely that you'll see it too

The trouble is with any unencrypted (or at least non-signed) watermark is that you have no way of proving that you added the watermark afterwards! If you are trying to protect your images from misuse then it will certainly require, at the very least, some form of cryptographic signing process that's embedded in the watermark - so that you can prove that you generated the image and the signature.

Stenography is the wrong word to Google for. Look for "image watermark protection".

EDIT: Here are some links:
http://www.riecks.com/security/
and http://en.wikipedia.org/wiki/Digital_watermarking
comparison: http://watermarker.com/how-to-ptotect-digital-images.aspx

HTH!
Matt