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Terrorists and steganography
ZDNet ^
| September 24, 2001
| Bruce Schneier
Posted on 10/10/2001 5:08:55 PM PDT by Straight Vermonter
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I thought this was interesting.
To: Straight Vermonter
So what messages were buried in Bin Laden's message of last Sunday? Any thoughts?
2
posted on
10/10/2001 5:15:51 PM PDT
by
alethia
To: Straight Vermonter
On the way home today I was listening to Kim Kommando (babe !) talk about this hidden text in pictures. I looked for a source in the pics to see what they were talking of and couldn't find the alphanumeric text they spoke of that could be looked at or altered ?
Anyone know how to do this to a picture ?
3
posted on
10/10/2001 5:20:07 PM PDT
by
Squantos
To: Straight Vermonter
If the NSA can keep a database of images (wouldn't that be something?), then they can find ones with subtle changes in the low-order bits. Way too wasteful. The number of images on the web is, well, mindboggling. Many of the images are copies of each other, some of them with small variations from corruption, morphs, edits and such stuff.
What you need is something like this tool:
"Stegdetect is an automated tool for detecting steganographic content in images. It is capable of detecting several different steganographic methods to embed hidden information in JPEG images. Currently, the detectable schemes are ..."
4
posted on
10/10/2001 5:24:06 PM PDT
by
Cachelot
To: alethia
The messages that might have been hidden in Bin Ladin's video last Sunday would not have any relation to steganography. His video may have included code words or gestures for his flunkies to pick up on. In the gulf war pilots who were shot down signalled their superiors with gestures or just their posture.
To: Squantos
There's computer programs that do it. It is also used as a way for artists to sign pictures electronically. Not too long ago it was recognized in court as a legal signature.
To: Cachelot
"Stegdetect is an automated tool for detecting steganographic content in images. It is capable of detecting several different steganographic methods to embed hidden information in JPEG images. Currently, the detectable schemes are ..." That is actually what got me looking for info on this. Tony Snow mentioned today that a company had done an exhaustive search of the internet for these messages and turned the information over to the government.
To: Straight Vermonter
Schneier is excellent; his
Applied Cryptography is pretty much the standard text for people learning computer crypto. It doesn't quite stand alone. It's light on crypto history, and not completely up to date; there's nothing about quantum cryptography, for instance.
If Ashcroft gets his way, we will be circulating these works in samizdat.
d.o.l.
Criminal Number 18F
Does this explain "Bert"?
To: NovemberCharlie
Yeah I just ruined a perfectly good pic of a B-52 Bomber. I opened it up with notepad and entered a line of text and saved it . When I tried to open it again it wouldn't. Said it was corrupted......oh well, I 'll play with it till I figure it out , self taught so far, albeit not very far :o)..........Stay Safe !
10
posted on
10/10/2001 5:34:03 PM PDT
by
Squantos
To: Squantos
Try reducing the message to a binary code (ASCII or not). Then open the message in Photoshop or some other graphic editor. Say, invert every 15th pixel if it's a one, leave it alone if it's a zero. If the picture is sufficiently busy, you wouldn't be able to see it. Time consuming I know, but it would work. There's also a method invented by Francis Bacon for hiding a message in another plain text message.
To: Straight Vermonter; Squantos
Just so everyone knows..... this was published here on FR closer to the original date of publication (9/24). I'll see if I can dig it up and post the link to the original thread.
To: Squantos
"Anyone know how to do this with a picture?"
Simplest way would be to open the picture in say .jpg or .gif format (or .bmp) or other formats with a text editor and look for hidden code. Sometimes in binary newsgroups my browser opens them as gibberish rather than the picture relatively often (a nuisance to a normal binary newsgroup user) but could be done on purpose.
I'm not real up on it, but some formats have unused bits for text that are transparent and you would have to know where and how to look for them like in Photoshop or PSP. I saw a discussion about it on one of my graphics newsgroups but at the time they didn't think much info could be transmitted that way. I thought otherwise.
There would be other techniques using layers (some practically invisible) and isolating the layer with the message, such as in a .pdf or .psp file for download. I thought about trying it myself as a joke before all this happened but didn't get around to experimenting with the idea.
There are probably other imaginative ways to conceal a message just about anywhere on the net. Usenet newsgroups would be a good place to send prearranged signals in regular language although they are mostly in English I believe.
13
posted on
10/10/2001 5:45:25 PM PDT
by
Aliska
To: Squantos
Yeah I just ruined a perfectly good pic of a B-52 Bomber. I opened it up with notepad and entered a line of text and saved it . When I tried to open it again it wouldn't. Said it was corrupted....
LOL! Yeah, that would be about what I'd expect to happen. ;)
It's a little more subtle than that. Remember that computer data is stored as bits and bytes. What steganography does is very subtly tweak the low-order bits in a picture or sound file, in order to encode hidden data within the file. The reason it stays hidden is that tweaking the low-order bytes results in changes to the original that are basically imperceptible no the naked eye (ear, for sound files) - think of it as just ever-so-slightly shifting colors by one shade darker, and you've got a good mental picture of the changes that result.
Anyway, as the previous poster said, you need specialized software to encode and decode steganographic information.
StegoArchive.com is a good source of various programs that hide information steganographically. Neil Johnson's
steganography and digital watermarking site is a good theoretical and technical introduction to the mechanical nuts-and-bolts of how information hiding is done.
To: Straight Vermonter; Squantos; ALL
To: Squantos
16
posted on
10/10/2001 5:46:06 PM PDT
by
spunkets
To: Straight Vermonter
Tony Snow mentioned today that a company had done an exhaustive search of the internet for these messages and turned the information over to the government. They may have made a good showing, but an "exhaustive" search they didn't. Too much data, the content is fluid, not all stego can be found with statistical methods (the company that makes Stegdetect also makes another product, OutGuess - "anti-statistical" steganography). Plus the fact that you don't necessarily need to hide things in pictures. There's stego for sound-files too..
17
posted on
10/10/2001 5:48:09 PM PDT
by
Cachelot
To: general_re
Crap.
low-order bytes = low-order bits
To: Squantos
Open the file in a word processing program. You get code. Add text to the file, the next person to open the file in a word processing program can read the text. Pic is unchanged.
To: Straight Vermonter
I've been wondering whether government surveillance of the web may be responsible for slowing it down. There are other influences too, of course, including people looking for news about September 11. But what would be the effect if Carnivore and hundreds of other supercomputers were constantly scanning sites on the web, looking for information. How much effect might it have? Can anyone hazard a guess?
20
posted on
10/10/2001 5:49:46 PM PDT
by
Cicero
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