Printable View
Okay, the thread wasn't about what stenograpy is, it was about a useage of it.
Lotta> The problem is whatever program you are using to do the code. You are most likely using some cheep program that is only used to demo what you can do with steno... A real program will not only allow both small and capital characters, it breaks up those characters so that they are stored in more then 1 spot.
Steganongraphy might not always be the most secure way to hide your data. It optimizes amount of embedded information while not particularly caring for security. So the stegdetect could identify an image which potentially contains your hidden data which is half the work to finding what is hidden.
If you have something that you want kept with even more secrecy, might want to try watermarking. Watermarking trades off amount of hidden data for secrecy and imperceptibility. So you cannot embedd as much but what you embedd is much(orders of magnitude) more secure. This is because data is embedded in a robust way and is more tightly coupled with content data (pixel information or audio samples). For instance steganography aproach might be to flip LSB of pixel data according to message to be hidden. Thats easy to analyze. Watermaking spreads bits of information across only significant pixel data in a more robust way. Significance of data is determined by watermark algorithm which can sometimes incorporate spread spectrum techniques, or perceptual entropy of pixels values or audio samples. This makes it hard to analyze.
There is a good discussion about both steganography and watermarking, which are sort of sister sciences, on watermarking forum.
http://www.watermarkingworld.org/WMM.../msg00018.html
You can imagine the million ways on how this can be used (good and bad).Quote:
Steganography is the art and science of hidden communication.
I first came across steganography by a newletter... i had never even heard about it, but anyways i'll provide you the links to Infopackets explanation on the subject. Very user friendly talk, easy to understand:
Part 1: http://www.infopackets.com/gazette/20031125.htm
Part 2: http://www.infopackets.com/gazette/20031127.htm
Part 3: http://www.infopackets.com/gazette/20031204.htm
Go ahead, give it a look.
Where is slarty? Reading his stuff, you can see some good ideas on stegnography.
(BTW, I'm no expert on this subject, but I try to study it in my free time) To truely hide your data, you need to have the only copy of the original file you are hiding the encrpyted data in. If anyone else has an original copy without anything hidden in it, sooner or later someone will realize that while a file they found somewhere looks similar, but it isn't 1:1...
The reason the original poster's program is converting it into single case is because it helps make it easier to "hide" the data, I assume. Although I'm not exactly sure how it would figure your message out from only lowercase characters without a key or anything that it generates for you, etc... Anyways, if you are reading someone's shopping list with randomly capitalized characters, it would seem odd... (Ok, the example below is a bit exagerrated)
What would you think the secret message is? MEET ME AT ONE!Quote:
Tim_axe's Shopping List:
1. one carton of Milk
2. five swEEt Tarts
3. sixteen ounces of MEat
4. ten heAlTh bars
5. sOme Natural pEas
Since you know that my shopping list should be all lower-case, because those words shouldn't be capitalized like they are, you know what the original data it, and you would be drawn to the things that don't belong. Same with cryptography in JPEG images, or anything else. A while back I took an image and played with the contrast and color balance to show that the "white" section of an image wasn't really white. Although I couldn't determine the message, I knew that something was up since it wasn't white when it should have been. (Search the Cryptography forums for that thread)
phorvati - I think water marking is a bit different since it is meant to be detected, or withstand torture of resizing, recompression, etc. A good watermark would be right through the middle of an image with your website name on it in bold black letters, although most people want ones that are more difficult to detect or not as unsightly. The watermark is designed to protect your work of art from being claimed by someone else (stealing your hard work). Not necessarially hide encrypted data, though it could hold it's ID number in a database of a company that manages such things I think. A tutorial on securing your images for websites was posted in tutorials or webdesign a while back, and even featured elsewhere on Internet.com. The author knows more about it than I do. (I forgot who wrote it though :( )
Hopefully this explains a little bit about stegnography or explains why your list is all lowercase...?
-Tim_axe
Yes comparing the two images 1:1 they look diferent. But the difference could have come from re-compression to a lower bitrate, printing/scanning or some other modification.
And if the difference came from stego or watermark type of information added to the image, then taking the difference would reveil hidden information in one of its forms. Even the cyphertext has a defined alphabet. So analyzing the hidden information will reviel steganographic information(encrypted or not) faster than a secret watermark information could be extracted.
So if I want to send you some important info, such as CC# or anything that I absolutely don't want revieled, I would rather go with a mp3 watermarking algorithm than the mp3-stego. Because mp3-stego alters LSB. And thats easy to analyze. Watermarking might put a bit in every frame of mp3 where stego puts in a lot more, but my priority is security, and not the amount of embedded data.
So although you hear about watermarking for preventing copyright violations, watermarking can also be utilized in many other applications. The important aspect is that its more secure, and survives intentional removal and discovery of information.
I was watching nbc news last night, and they had a report on this picture of niagara falls on an al qaeda website. The website showed all kinds of pictures of locations that were taken before a terrorist event happened. So like, the twin towers still standing was an example. Then at the end of the list, there was a picture of Niagara falls, and they said that there hasn't been a terrorist even there yet, and it could be some kind of signal. They also said that they had reason to believe that the picture had an encoded message on it. They didn't say steganography, but it sounded a whole lot like it. I havent been able to find the pic, I think its on some al qaeda website and im afraid to go looking through them, but if anybody knows what I'm talking about, or knows where that pic of niagara falls is, it would be pretty cool if someone could post it and we could try to crack it or something. It's a pretty good example of what stegangoagoagnraphy is for.
tonybradley's idea is the same as my project [well, an extended essay for which I will need to code some tools for]. basicaly, taking the data - string or whatever - and encrypting it using one of the strong algorithms out there, then hiding the block in a file. like this you have protection by crypto [passphrased and hard-crypted], by stegano [picture embedding] and by obscurity [which is the very principle of stegano anyway].
as for Lotta's question, if what you are saying is that you can only use capital letters for your string, I think that's a software issue rather then a limitation with steganography. of course, please correct me if I'm wrong, but otherwise you should ckeck-out other tools.