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Battling Steganography

CmdrTaco posted more than 13 years ago | from the why-would-you-want-to dept.

Encryption 195

An anonymous reader submitted a fairly thin little story about a researcher who is Battling Steganography. I can certainly see the appeal of the study but it really seems like a needle in a hay stack sort of project. And when you actually can detect one technique, new and better techniques will crop up and take its place.

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very suspicious (0)

kaldari (199727) | more than 13 years ago | (#2109642)

The guy in the photograph has no eyes! Maybe he stared at his monitor a little bit too long. In fact, is it just me or does he look like a cardboard cutout. Very suspicious. I bet there's a hidden message imbedded in that picture!

Wait a minute (5, Insightful)

imAck (102644) | more than 13 years ago | (#2111109)

Was it just me, or did the article make it seem like anyone that would use steganography would be a criminal? Since when in a 'free' country should the ability to hide a message be of interest to the "legal community"?

Re:Wait a minute (4, Insightful)

DeadVulcan (182139) | more than 13 years ago | (#2113599)

Was it just me, or did the article make it seem like anyone that would use steganography would be a criminal?

The article didn't say this at all. In fact, the types of criminal activity that were mentioned were "political and corporate espionage or illegal pornography."

Talking on the phone is not criminal, but wiretaps are used all the time in fighting organized crime.

Re:Wait a minute (1)

cavemanf16 (303184) | more than 13 years ago | (#2138514)

Since when in a 'free' country should the ability to hide a message be of interest to the "legal community"?

Secrets that suddenly can be made not secret amounts to huge amounts of money in many cases, that's why. Tobacco companies tried to 'keep secret' the fact that their product was highly carcinogenic for years. When the 'secret' was finally let out, guess who made the most money off of it? I've got a Forbes magazine from a month or two ago sitting at home that details how certain lawyers have made billions of dollars (USD) off of litigating corporate 'secrets.'

Re:Wait a minute (2)

jandrese (485) | more than 13 years ago | (#2144384)

Great. I can give my money to the Tobacco companies...or to Lawyers. Maybe I should just burn it instead.

Re:Wait a minute (1)

rgmoore (133276) | more than 13 years ago | (#2119561)

No! That burning money would create carcinogenic smoke, attracting more lawyers and starting the cycle of lawsuits all over again. Recycle instead.

Re:Wait a minute (1)

Another MacHack (32639) | more than 13 years ago | (#2135024)

Careful, the fumes might give you lung cancer..

Re:Wait a minute (0)

Anonymous Coward | more than 13 years ago | (#2143649)

Great. I can give my money to the Tobacco companies...or to Lawyers. Maybe I should just burn it instead.

If you buy lots of cartons of cigarettes, you can do both!

I love Katy! (-1, Offtopic)

Anonymous Coward | more than 13 years ago | (#2111385)

But Katy does not love me! Or so she says.

Re:I love Katy! (-1, Offtopic)

Anonymous Coward | more than 13 years ago | (#2131841)

It's becasue you have a small unit.

Re:I love Katy! (-1)

mackga (990) | more than 13 years ago | (#2140009)

you all fucking SUCK!

eat shit and die

What's the point? (0)

Anonymous Coward | more than 13 years ago | (#2111574)

So what if he can predict the likelyhood of a hidden message. He still can't decipher it.

Staganogrphy as a whole seems unneccessary and overlike complex. I couldn't care less if you can see my message. You'll have a hell of a time reading it, thanks to encryption.

rieu ro,SZE98U=[GMLC #$%*UJHNMPO(I&%$sdfghjkl

Understand what I'm saying?

Who writes these captions ? (3, Funny)

dingbat_hp (98241) | more than 13 years ago | (#2114018)

... The secondary image, woven into the primary one, would not be possible to detect by peeling up one corner of the main image (as has been done here merely for illustrative purposes).

Excuse me ? Did I wander into The Onion [theonion.com] by mistake ?

Re:Who writes these captions ? (0)

Anonymous Coward | more than 13 years ago | (#2138512)

The people who write the articles here at Dartmouth want to impress people, they have no clue what they're writing about. Our administration is full of idiots.

Statistics are bullshit. (1)

Sergeant Rock (204109) | more than 13 years ago | (#2114848)


I like the way he claims a 90% success rate. Either the researcher is a moron or else the person writing the article has already beaten him there.

What if there were three encrypted messages in each image he processed? Finding one is useless, because the sender could put an easy message in and two extra that won't get caught.

Better yet: his algorithm could be giving him garbage hits and not be finding anything real. The pictures could be just pictures. Novel concept.

*whew* Moron alert - eleventy three o'clock.

Re:Statistics are bullshit. (0)

Anonymous Coward | more than 13 years ago | (#2117978)

let's say for every image you send you run a simple script that generates X size file from /dev/random and stuffs it into those images.

you do exactly what the brits dod during WW-II send thousands of fake transmissions to conceal the real ones. if the detector always goes off on your images then they will become lax or ignore you.. now, get hundreds of people doing the same thigng... Voila detection system broken.

Patterns in lowest bits (3, Informative)

Fencepost (107992) | more than 13 years ago | (#2115793)

I haven't actually done any digging on this, but I suspect that for almost any graphic image there are detectable patterns in the ordering of the lowest bits. There will of course be some files (particularly small ones) where there isn't enough information to identify patterns, and there will be others where the distribution truly is random, but that just means that identifying files with steganographically-encoded information won't be a 100% accurate process.

That lack of certainty really isn't that big an issue, because with a good idea of what percentage of images are false positives it would be fairly simple to look for image sources where the percentage was well outside the norm.

All of this would of course be very resource intensive and would require access to large amounts of data (Omnivore, anyone?) but it's far from outside the capabilities of most governments.

Possibly also of interest to people is Benford's Law, which relates to the distribution of numbers - turns out that in many areas it's very simple to identify real data vs random data, because real data has some definite non-random properties.

Steganography (-1, Offtopic)

Anonymous Coward | more than 13 years ago | (#2116116)

I've been working on steganography for over 10 years and can tell you it kicks ass.

Sincerely, Mike Bouma

Prof. Farid (1)

Negadecimal (78403) | more than 13 years ago | (#2116499)

Anonyone wanna bet that Farid is the AC who submitted the story? I took a programming class from him a few years ago...he seemed pretty full of himself then, too.

p0rn grant (0)

jrwillis (306262) | more than 13 years ago | (#2117361)

Sounds like this guy has managed to get a grant to look at p0rn. "No, I'm not looking at p0rn, I'm looking for hidden messages." :)

FP (-1, Offtopic)

Anonymous Coward | more than 13 years ago | (#2118111)

FP nigga gook! you damn chink!

skeptical (-1, Flamebait)

Anonymous Coward | more than 13 years ago | (#2118112)

I wonder how many 'criminals' use all of this crazy awesome new technology out there. Yea there is credit fraud and supposed 'cyber terrorism' but damn, maybe these people deserve these credit card nums for being more intelligent than most criminals.

Re:skeptical (0)

Anonymous Coward | more than 13 years ago | (#2135351)

I once saw a CIA statistic that claimed that Osama Bin-Lauden was resonsible for 23% of all "free porn" sites on the internet.

[The Weathermen ate my balls.]

Re:skeptical (0)

Anonymous Coward | more than 13 years ago | (#2145382)

"responsible" (stenographically hiddedned message informing his CIA controller that he as "p"eed on O B-L.)

This confirms my suspicions. (0)

Anonymous Coward | more than 13 years ago | (#2119837)

I am now certain that the goatse.cx picture is just a vector for steganographic messages to Russian Federation field agents. I think Dr. Farid should concentrate his efforts there.

~~~

What about deniability? (3, Interesting)

(void*) (113680) | more than 13 years ago | (#2120095)

Suppose one gets caught with such an image. According to him, the technique has a 90% chance of success. So what about the 10%, wherein, one has no message encoded in an image, but triggers tha alarms anyway? If you get caught by the FBI, what can you say?

You might say that 90% is no pretty significant. But considering how many actual images are there out there with actually no steganographic message, I think you'll actually end up persecuting more innocent people.

I just more more eveidence than this is required for a warrant to be issued.

Re:What about deniability? (2, Insightful)

Anonymous Coward | more than 13 years ago | (#2139674)

A 10% miss rate doesn't mean that there is also a 10% false alarm rate.

Impossibility (4, Informative)

zpengo (99887) | more than 13 years ago | (#2123204)

Steganography is nothing new. People have been hiding secret messages in innocuous objects since time began. Naturally, various people want to prevent this, but the method's very nature makes it almost impossible to simply track.

Not Quite Useless (3, Insightful)

lblack (124294) | more than 13 years ago | (#2125289)

While it's true that human beings can interpret images to mean something that a machine could never pick up on, that's not the thrust of the research being done here.

He is doing research into a very particular kind of steganography, whereby messages are concealed within an image via slightly altering the least significant bits of an image.

When you encode information in this way, somebody knowing how to extract it can pull out a message which is not subjective (as in the example of interpreted images given by another poster), but rather is very concrete.

There is some evidence that this form of encoding has been used to communicate information throughout terrorist cells.

What the researcher is doing is developing a method to detect when the LSB's in an image have been manipulated slightly. He is not trying to decode the message, but only to flag particular images as being suspicious.

Decoding would be a matter for someone completely different -- like the FBI, for instance.

His method does have applications, and if it is through alteration of LSB that a message is embedded in an image, it will apparently detect such 90% of the time.

This is a vast improvement over any existing methods I know of for detecting LSB manipulation.

So he's not quite looking for a needle in a haystack. He's examining millions of haystacks, and pinpointing the ones that probably *do* have needles in them.

Quite a large difference, really.

-l

battling privacy? (1, Insightful)

Anonymous Coward | more than 13 years ago | (#2126867)

So is this guy also battling privacy?

I don't see how anyone with a conscience could decide to intentionally try to destroy methods with which people can protect their privacy.

Re:battling privacy? (0)

Anonymous Coward | more than 13 years ago | (#2122083)

Apparently the guy is under the impression that steganography is only used by criminals.

Re:battling privacy? (-1, Flamebait)

Anonymous Coward | more than 13 years ago | (#2131755)

Why is privacy so great?

Re:battling privacy? (1)

Daniel Dvorkin (106857) | more than 13 years ago | (#2129726)

Pretty ironic question coming from an AC.

Re:battling privacy? (0)

Anonymous Coward | more than 13 years ago | (#2128569)

Yeah :) I thought about after I posted it... I didn't say privacy was bad, I was just wondering why everybody always talks about privacy as if it is the greatest thing ever, and the God-given right of every person. Privacy can be used to hide some pretty awful things. If there were no privacy at all, there would be no misinformation (of course this is being overly optimistic).

Privacy is crucial (-1, Offtopic)

Anonymous Coward | more than 13 years ago | (#2124862)

A certain degree of privacy is crucial to The MAN in keeping control.

If we had a 100% transparent society:
  1. The people could keep tabs on his skullduggery
  2. We'd find out just how common " aberrant " behaviour really is... ("Just say no", cheating on taxes and goat-worship)

Obviously, the very foundations of our society would crumble if we didn't have some privacy.

Re:battling privacy? (1)

crenshaw (92320) | more than 13 years ago | (#2132471)

Wake up. Unless you are happy and want to permanently settle on the present stenographic techniques, you need people like this dude to figure out how they can be defeated. Imagine if you had said the same thing when "ROT-13" was invented.

Can he decode stereograms? (-1, Offtopic)

Anonymous Coward | more than 13 years ago | (#2127111)

This would be great for my mom. She just can't make a surfboarder out of that tiled fish background.

This is Wonderful News (5, Insightful)

crisco (4669) | more than 13 years ago | (#2128058)

The reason we have effective encryption (when it is implemented right) available to use is because of the large amount of research that has gone into breaking encryption. Because of the community of mathematicians and others actively trying to break weak algorithms we know the strengths and weaknesses of various ways to encrypt data.

Now we have more people looking at steganography. This can only make it more effective. Sure, the methods we have now might be broken but what about the next ones, the ones that don't show up on the statistical analysis that he appears to be using.

Not a waste of time... (2)

Junior J. Junior III (192702) | more than 13 years ago | (#2129037)

...new and better techniques will crop up and take its place.
Two responses to this observation come to mind: "Duh." And, "So?" Obviously, once an encryption scheme is cracked, people will stop using that method and try to find a new method. But this will only happen after it is known that the encryption is being broken. Thus, there is a window of time, however short, during which the encryption cracker will be able to intercept and read encrypted messages as plain text. Therefore, cracking encryption is a useful enterprise. It's stupid to act like it doesn't make any sense to defeat one encryption scheme just because another one will eventually replace it.

Steganography in movies (1)

EMH_Mark3 (305983) | more than 13 years ago | (#2130226)

Wasn't that what the kids in Along came a Spider used to chat in class? Somekind of over-simplified version of it, anyways ^_^

This could be fun... (1)

evilgrin (128415) | more than 13 years ago | (#2131056)


...if his research leads to easy ways to decode and search image files for hidden messages.

Can you imagine using his techniques to search through Google's image archives, or perhaps a gnutella network just to see what is sitting out there?

This sounds like it could uncover yet another seedy underbelly of world culture.

I imagine there could potentially be millions of hidden messages out there that noone knows about.

The ancient Greeks di dit this way (0)

Anonymous Coward | more than 13 years ago | (#2131078)

They shaved a messenger's head, etched in a message, let his hair grow back, and sent him on his way.

Re:The ancient Greeks di dit this way (0)

Anonymous Coward | more than 13 years ago | (#2139879)

Here at NSSSL (National Sooper Secret Snoopers Laboratory) we're still using that technique. According to the DMCA, you are Fucked! Prepare to receive letters from our lawyers!

Did you know? (-1, Offtopic)

Anonymous Coward | more than 13 years ago | (#2131079)

78% of Jews admit that they have seriously entertained thoughts of having sex with animals. 77% admit that they have gone through with it.

Re:Did you know? (1)

chartreuse (16508) | more than 13 years ago | (#2117360)

I think yr stats are way too low -- or are humans not animals?

Re:Did you know? (-1, Offtopic)

Anonymous Coward | more than 13 years ago | (#2111516)

Only a filthy Jew trying to statistically link himself to normal humans would classify the human race as animal

Re:Did you know? (-1)

Ralph JewHater Nader (450769) | more than 13 years ago | (#2135296)

Now that's an idea worth researching... but jews are by definition subhuman, they're probably trying to drag the rest of humanity down to their level. Maybe the niggers and the dune coons also belong down there, but definitely not the superior Aryans.

some thoughts (3, Interesting)

Proud Geek (260376) | more than 13 years ago | (#2131394)

First, Taco's comment about "new and better techniques" is ill-informed. This is an information-theoretic method, where the inclusion of hidden information alters the nature of the information in the original document. What this technique does not give you is any hint on how to extract the hidden information.

Second, I'm not sure how to react to this. I don't use steganography to hide information, nor do I encrypt my email normally. I guess it's good to know if the techniques used to do this are detectable or breakable, but if it was actually used on a large scale you can bet I'd be screaming, "Big Brother!!!"

Not too plausable of an argument (2)

Lumpy (12016) | more than 13 years ago | (#2131753)

The fact that an image after altered can be detected via a mathematical function is true, but saying that it can be detected without having a source image to begin with? What If I take a picture of a random image and then stuff the message which was encrypted into the image. Voila undetectable. Randomness makes the perfect concealment.

I can see detectability from some of the crude software packages out there, but not the better ones that make sure the applied file is expanded to the size of the image and reversed.

Re:Not too plausable of an argument (1)

DahGhostfacedFiddlah (470393) | more than 13 years ago | (#2124541)

I'd assume that they're working with photographs and photograph-like images (as opposed to stick-man drawings or something like that). In that case, the function could look at certain things that would appear in a photograph - colour borders, gradient, etc. If the picture consistently doesn't show what's expected, then that could be used to show that there's been some sort of change made to it. I don't know much about graphics analysis, so I couldn't say for sure, but I can see this working.

Wrong. (1)

kurowski (11243) | more than 13 years ago | (#2133213)

Randomness makes the perfect concealment.

Actually, randomness makes piss poor concealment. Any data encrypted by a decent algorithm looks random. And that makes it looks suspicious to the spooks ("Yup, he's sending another 10MB of "random" data to the anonymous remailer again.").

The whole point of steganography is to hide a message in innocuous data. The kind of data that people send most frequently, and is likely to go unnoticed. Stuff like digital photos, audio, etc.

Your average image has a fairly predicable amount of randomness in it. What he's done is basically found a statistical way to identify if an image has more randomness than you'd expect in a similar picture. Your random image would probably set off all kinds of alarm bells in his system.

Re:Wrong. (2)

Lumpy (12016) | more than 13 years ago | (#2155757)

Ahh but that's the point.
I take a picture If a room and the Television has only static on the screen... Pretty innocent picture, except the tv screen holds DeCSS.c or The chemical forumla for Cokeacola.

There is a large amount of randomness in the world. A photograph taken during a rainstorm, an artsy photo of sand.... etc...

I can give you many many innocent looking photos that have quite a bit of randomness in them. (and a few nicely staged UFO photos, but that my hobby :-)

Re:Not too plausable of an argument (1)

Syris (129850) | more than 13 years ago | (#2157936)

It's the statiscical properties of image files that he's exploiting to "detect" hidden info.

Apparently the LSB's of any image file tend exhibit certain mathematical qualities and inserting data upsets those qualities while not interfering with the quality of the image. Kinda nifty.

I don't see how this can work (1)

eXtro (258933) | more than 13 years ago | (#2131794)

Mix steganography with good encryption and/or coding and it seems impossible unless you know before hand what the unadulturated image is on a bit per bit basis.

For instance two diffent jpeg encoders, both at the same quality level will result in subtly different encodings of the same source image. If you take these two images, calculate the difference at each decoded pixel, and amplify the diffence (so that you can easily detect minue intensity differences) you'll see the signature of the differences between the encoding engines.

Now if I encode a message in the image (a 1 megapixel image, small by todays standards, can encode a 1 megabit steganographic message assuming only a 1 bit change in colour). If you could get the source image and do the above described difference calculation you would see the pattern representing the message.

If you pick the wrong source image (it LOOKS identical but was compressed slightly differently), you'll only reveal a combination of the signature and message.

Do whatever statistical examination of this noisy signature you want, I don't see how you can determine that the image concealed data. Well, unless you do an impressively poor job of concealing the data in the message. Encoding your message in a pure white gif, jpg or png would be a bad idea for instance.

Watermark detection (1)

KurtP (64223) | more than 13 years ago | (#2131824)

Seems to me that a watermark is a form of steganography. I wonder if these techniques would work for watermark detection?

see provos' work (2, Informative)

nobody/incognito (63469) | more than 13 years ago | (#2131868)

neils provos (openbsd and openssh developer) has a stego detector based on similar principles (i.e., look for statistical anomalies in jpeg files).

in fact he is presenting a paper on the subject at the usenix security conference tomorrow.

unlike the dartmouth folks, who apparently think press reports are the proper medium for scientific interchange, provos makes his results publicly available; see

http://www.citi.umich.edu/techreports/

reports 01-1 and 01-4.

nobody

Talk about arrogance... (1)

PRobinson (471021) | more than 13 years ago | (#2132345)

And when you actually can detect one technique, new and better techniques will crop up and take its place.

That's like saying 'if somebody can break 56-bit keys, you can just increase the key length'. In other words, it's really not that simple. Firstly, you're assuming that there will always be new techniques. Secondly, you're suggesting that these new techniques will always be harder to detect than previous techniques. Thirdly, you're assuming the licensing model of such techniques will allow them to take the place of existing techniques.

In short, until you know what you're talking about, or are able to engage your brain, please shut up with your opinion, and just deliver articles and facts. Thanks.

Re:Talk about arrogance... (1)

fyonn (115426) | more than 13 years ago | (#2142685)

I'd say there is obvious precedant for that statement. stenography has moved from being invisible ink, through acrostic literature[0] to the current practise of embedding data into images or sound files. I'd say that if you graphed it it would imply that we have a lot more ways to go.

the very history of this planet (or at least of the humans on it) says that we have a tendancy to work out more and more complex ways of getting past these restrictions (I hate to get all dr malcolm on you "live will find a way").

as with many things (virii, firewall's, weaponry, speed guns, etc), it's a race between those who seek to subvert the system and those who seek to enforce the system. one is always playing catchup to the other and is unlikely to come to an end until we all have brain slugs attached. we're cunning buggers us humans.

dave

[0] - if you write acrostically then you embed a message in your text by using the first letters of each word or sentance or whatever to spell out your secret[1].

[1] - go read godel, escher and bach, has a section on it, good stuff.

So this guy can predict hidden information? (3, Interesting)

Bonker (243350) | more than 13 years ago | (#2132346)

The article stated that the guy used an algorithm to detect statistical variations and predict wether an image had steganographically hidden data 90% of the time.

How about a GIMP or Photoshop plugin to randomly insert junk data in any JPEG saved in order to make this technique useless? It'd be fun to the the NSA sit and fret over an image that apparently had a list of Warez traders and DMCA violators but instead contained the lyrics to 'Penny Lane'.

Better yet, how about an Apache module that does this same thing to every JPG it serves?

The point is, that as soon as it becomes common procedure to intercept images to check for steganography, those who use steganography will switch methods. I bet PGP data encoded in a JPG is a lot harder to detect, and infinitely harder to extract.

Re:So this guy can predict hidden information? (2)

Contact (109819) | more than 13 years ago | (#2138004)

An Apache module which automatically inserted noise into JPEG images to simulate steganographically hidden messages is a good idea...

The problem is that it would corrupt any real steganographically hidden messages in the images, hence rendering images a bit of an unreliable mechanism for storing hidden text... ;)

Re:So this guy can predict hidden information? (2)

YoJ (20860) | more than 13 years ago | (#2119451)

No, this would actually be really cool. Make an Apache module which automatically inserts something steganographically into every JPG it serves. Some people put encrypted data into the images, and others just direct it to read from randomly encrypted gibberish. Then the government has to deal with lots of script kiddies who think they are cool by embedding Brittney Spears mp3s into the images from their webpages.

Re:So this guy can predict hidden information? (1)

fyonn (115426) | more than 13 years ago | (#2121878)

well.. if the junk is properly stenographed so you can retreive that junk (although penny lane isn't junk, good song :) then you can use the lyrics and the knowledge of stenographic technique to restore the picture to it's former state, at which point you can run the stenography detecter again and get the real secret...

of course it gets more cunning when the data you remove stenagraphically is itself an image with stenographed data on it, and that data is...

and eschelon has a machine do do all this but completely missed your bombing plans which were the subject of the picture itself and not the stenographed data itself... hiding the wood in the tree's as it were.

dave

I think I speak for all Slashdot users... (0, Redundant)

gergi (220700) | more than 13 years ago | (#2132380)

Huh?

Re:I think I speak for all Slashdot users... (0)

Anonymous Coward | more than 13 years ago | (#2124540)

How about you actually *read* the article before you post?

This could not be held up as evidince (1)

Phaser6047 (70775) | more than 13 years ago | (#2132914)

How could something like this be held up as any sort of evidince. From what I interpret of what this guy is trying to do is check if that there may be data by checking with compression rates, and randomness compairsons. But what if the photograph or audio file is inherently noisy? Or what if you use a poor implimetation of the compression algorithim?

With standard encryption, if you are in court you can be ordered to decrypt it, but if there is a chance where there is nothing there, they can't force you to do anything.

This just seems to be a waste of time to me.

Damn! (1)

Phrack (9361) | more than 13 years ago | (#2133317)

And I was writing on my screen with lemon juice and mailing the laptop!

(note: lemon juice was one of the first "invisible inks")

F u cn rd ths ... (3, Funny)

graybeard (114823) | more than 13 years ago | (#2133676)

u cn b a stngrfr!

Re:F u cn rd ths ... (5, Interesting)

dschuetz (10924) | more than 13 years ago | (#2121039)

If steganography can be made "turnkey", it'll work
for most of today's privacy requirements.

You might think that it'd be easy to detect,
or simple to prevent, but that's simply not true.
Unless someone lists all the ways in which one

can hide information, and a fantastically fast
approach to testing any given communication on the
net against those techniques. Otherwise, to

read a steganographically-encoded message,
each recipient will need to figure out which of
all the messages intercepted even includes the
data you're looking for, and what was used in

this particular instance. Hell, one might even
have two or more different techniques applied
in a single message. Like this message does.
Sort of.

....

Re:F u cn rd ths ... (1)

mlibby (142509) | more than 13 years ago | (#2135023)

i can be a stenographer? i thought you had to read (& write) shorthand to do be able to do that...

Re:F u cn rd ths ... (2)

wiredog (43288) | more than 13 years ago | (#2154084)

Sorry. Not steganography. That's compression. Steganography adds data. Compression removes it.

Re:F u cn rd ths ... (1)

taliver (174409) | more than 13 years ago | (#2128882)

Except I think that he was showing stenography...

There's a hidden message here! (0)

TrollMan 5000 (454685) | more than 13 years ago | (#2134212)

If you look closely in the subject of this post, it will reveal a hidden Satanic message!

Beware what you see!

How can you detect random noise? (3, Interesting)

Contact (109819) | more than 13 years ago | (#2134214)

Dislaimer: I'm not an encryption expert by any stretch of the imagination...

This is an interesting idea, but surely any good encryption produces an output which is indistinguishable from random noise. So, how can the algorithms mentioned in the article (which is interesting, but rather short on facts...) distinguish between the noise added by a steganographically embedded encrypted message and the noise caused by a slightly underspecced A to D converter?

I'm honestly curious... has anyone got any links to a more detailed report on this?

Re:How can you detect random noise? (0)

Anonymous Coward | more than 13 years ago | (#2118515)

If we're talking about digital cameras as carrier sources then it is not strictly true that the LSBs in an uncompressed ( that's where you should start ) image are truly random noise.

All but the most expensive dcams use some sort of mosaic filter over a monochrome sensor. The most common pattern is Bayer :

rgrgrgrg
gbgbgbgb
rgrgrgrg
gbgbgbgb

To get an RGB image the missing data are formed from neighboring cells. Various filters are used. The result is that there will be correlations with neighbors.

The generalized implication for steganography development is that the better the source characteristics are understood and quantified, the better the technique that can be designed for using that source as a carrier.

It looks like its time to kick it up a notch as far as stego goes. BTW the FBI has asked for and received funding for research into hidden data detection. Maybe this is one of their first academic grants.

m ( sort of anonymous but not a coward )

Re:How can you detect random noise? (5, Informative)

bartle (447377) | more than 13 years ago | (#2119591)

So, how can the algorithms mentioned in the article (which is interesting, but rather short on facts...) distinguish between the noise added by a steganographically embedded encrypted message and the noise caused by a slightly underspecced A to D converter?

You're right, there isn't too much of a difference between random noise and an encrypted communication. If you had a pure digital stream that had just been converted from analog, you could stick data in the least significant bits and no one would be the wiser. For example, a CD is just a sequence of 16 bit words iterated 44,100 times a second; you could just replace the least significant bit in each word with bits from your hidden message and it would be indistiguishable from random noise.

The problem arises when you try to compress digital information. These compression algorithms use the most optimum way to represent data that they can find and discard the least significant data, so they would completely destroy the afore mentioned hidden message. To hide data in a compressed file you need to play with how the compression mechanism stores the data, and the resulting file is most probably not going to be optimally compressed when you're done. What this guy is doing is looking at how the information was compressed, extract the overlying data that was being stored, and making sure the compression algorithm was indeed optimal. If there are any odd quirks in the compressed data or it doesn't look like the compression was optimal, it may be because data is hidden inside.

I hope this is a good enough explanation. I'm short on the examples but the underlying ideas are pretty basic.

Re:How can you detect random noise? (1)

fyonn (115426) | more than 13 years ago | (#2118404)

well, only lossy compression chuck's data. if you used gzip to compress an executable file then it had better come out the other end looking identical or someone will be annoyed. now if someone mp3'd that audio then fair enough. but you shouldn't generalise that all audio compression is lossy.

dave

Re:How can you detect random noise? (2)

BradleyUffner (103496) | more than 13 years ago | (#2142425)

lets say you take a picture with a very high quality digital camera and save the picture as an uncompressed BMP. When that file is converted into a .jpg tere are specific patterns in the file that show that it was compressed as a jpg. Colors are related to colors next to it, and you end up with odd compression fragments when the file is uncompressed. If a coded message is inserted into the jpg it will alter those compression patterns. The article talks about altering the least significant bit of color. in the JPG algorithem a small change like that would have drastic effects on how the image was compressed. By analizing those patterns they can tell if something odd was inserted into the file. They can't tell what it was, but they can tell the the picture was altered in some way. At least thats what I interpreted from the article, as alway, i could be wrong.

They're on to me!! (1)

the_ph0x` (170740) | more than 13 years ago | (#2134215)

Crap my underground pr0n ring is in danger now!! Better start embedding in mp3's...

.ph0x

If steganography becomes illegal (0)

Anonymous Coward | more than 13 years ago | (#2134514)

then only criminals will hide secrets in porn.

Battling Stenography? (1, Funny)

Anonymous Coward | more than 13 years ago | (#2135298)

Wouldn't good voice recognition software help?

I used to battle steganography (0, Offtopic)

WillSeattle (239206) | more than 13 years ago | (#2135299)

until I decided to let dinosaurs alone.

Seriously, whether it's typing profiles, mouse moves, misspellings, funny walks, all can be copied and can have inaccuracies that cause misidentification.

Besides, what would we do without steganographers? And steganographists? Subject them to stalactites and stalagmites by satellite?

Hidden meaning in hidden pictures (1)

WillSeattle (239206) | more than 13 years ago | (#2134608)

One should point out that you can also contextualize it, with a common base of painting for example - the use of certain background images or shades can have a meaning that a machine will miss, but a human can translate:

Picture of small boy holding a goose while reading a book = I am hungry for words.

Picture of a goose holding a book about a small boy = The feds are spying on me.

Picture done with buttons instead = no more bagels.

Re:Hidden meaning in hidden pictures (0)

Anonymous Coward | more than 13 years ago | (#2138271)

Jesus. Between that post and the one preceeding it, I have come to the conclusion that you really should lay off the crack.

Sexy MOBO (1)

richardmilhousnixon (515595) | more than 13 years ago | (#2135320)

My biggest fear is that someday people might be able to spread racy photos of motherboards around the world WITHOUT DETECTION! Will someone PLEASE think of the children.

Damnit Honey, I'm not oggling porn ... (1)

ReidMaynard (161608) | more than 13 years ago | (#2135321)

I'm researching Steganography!

Another reason for pr0n? :-) (1)

gosand (234100) | more than 13 years ago | (#2135545)

That is why pr0n is so prevalent on the net, people are communicating! ROFL. When I want to send my mom a message thanking her for my birthday card, I just hide that message within a fisting photo.

If anyone wants more info on this kind of thing (information hiding) pick up a book by Simon Singh [simonsingh.com] . I recommend The Code Book.

[shameless plug] Pounding Sand [poundingsand.com] Tshirts. Get your Micro$oft satire here!

First DMCA reference! (0)

Anonymous Coward | more than 13 years ago | (#2135578)

You know what I mean (or are you new here?)... If I'm trying to control access to something, isn't it illegal under the DMCA to circumvent my access control techniques? Suspicion of illegal activity is NOT ENOUGH reason (for non-law-enforcement types, at least) to go poking around in my data.

guns kill more people than steganography (1, Insightful)

Anonymous Coward | more than 13 years ago | (#2135906)

How come Dr. Farid is not
battling Guns?
Sounds like someone who should work for
a totalitarian government.

Resource Intensive (3, Interesting)

Gregoyle (122532) | more than 13 years ago | (#2137399)

I agree with the "needle in a haystack" idea. It doesn't seem like this technique would be practical given the relation between bandwidth and image size.

Given a certain state of network bandwidth, the quality of images transferred over the network is likely to increase as the ability to transmit that data increases. This means that anyone trying a large scale data mining for steganographic data, for example in a Carnivore-type application, would need to have many times the bandwidth of ALL the senders/recievers in order to analyze that much data.

That would make it so the only real application of this method would be for people you already suspect of sending steganographic data. You could direct the search toward them. However, then it is still trial and error to find which steganographic protocol they used, etc., and you're back to square one.

Maybe if the steganographic checking system was actually *intergrated* to the Carnivore system you could get somewhere. It might be a good way to search for messages that were "suspicious".

It is interesting, though, that this method is possible without knowing the individual steganographic protocols. It just seems that it would be too resource-intensive to deploy on a wide scale, and a wide scale is the only place it would be really more useful than trial and error.

1st anti sci*ntology post (-1)

sheeplover (461448) | more than 13 years ago | (#2138268)

sci*ntology is a cult led by john travolta.
slashdot is deeply involved with Sci*ntology.
you should leave slashdot now or they may brainwash you.
check out anti sci*ntology sites [aol.com]
Fight this cult now!

Whack a mole (2)

mikethegeek (257172) | more than 13 years ago | (#2138270)

What it boils down to is this:

The more the corporations, and their lackeys in government restrict freedom, the more determined those to preserve it will become, and the less effective their efforts will be.

For one thing, it's a challenge, and nothing inspires great accomplishments from hackers than waving the red flag.

It's still worthwhile. (1)

Christopher Craig (1394) | more than 13 years ago | (#2138392)

Even if it were a needle in a hay stack, which I'm not willing to admit that it is, I wouldn't say that it's not worthwhile. People have been practicing stenography for hundreds of years, and the technologies to find it have always been just behind.

For literally hundreds of years encryption technologies have stayed just ahead of cryptanalysis technologies. We now have entirely new criterium by which we judge crypto, and new methods by which we develop it. It used to be considered good data hiding to hide a message in a cake or a bottle. For a several hundred years it was accepted that the strength of a cypher was in keeping the cypher itself secret, now its thought foolish to have a cypher whose security remains on the secrecy of anything but the key.

Current systems are based on complex, provable, mathematical models. Quite a departure from the Ceaser cypher and a secret bottle cap. In spite of this, though, we still occasionally come up with something like a faster method to solve knapsack cyphers and turn the world around.

If you have any question of the value of good steno/anti-steno or crypto/anti-crypto, just ask Mary Queen of Scotts or thousands of dead U-boat sailors.

Thoughts on what he might be doing... (1)

rarose (36450) | more than 13 years ago | (#2139676)

We've all heard of "Security through obscurity", well his methods are "Detection through obscurity". Once his detector becomes public (or there is an open Oracle the way the SDMI challenge had) people will quickly alter their techniques to avoid it. Since there is virtually zero technical information in the article let me take a guess as to what he could be doing: Picture two rows of three pixels...
P11 P12 P13
P21 P22 P23
If the vertical rows have the same values *except* for the LSB of each [i.e. P11&0xFE == P21&0xFE && P21&0xFE == P22&0xFE && P13&0xFE == P23&0xFE], then the probability of an encoded message rises the more this condition exists thoughout the picture.
But it's easy enough to make an encoding algorithm smart enough to avoid that trap.

Battling Hany Farid and Other Privacy Snoopers (2)

Louis Savain (65843) | more than 13 years ago | (#2140043)

I suggest that we flood the net with documents containing hidden bogus messages. Maybe an innocuous worm or virus would do the trick. It could seek out audio and image files and insert random messages. That should keep the spying computers of the government and other freedom hating organizations busy.

But wait a minute, seeing they can enact freedom squashing laws like the DMCA with impunity, what's to keep them from making steganography illegal? Resist Big Brother. Demand freedom always!

hmmm (1)

zulux (112259) | more than 13 years ago | (#2140245)

whatT? would Hidien tExt damage Your retinaAs embedded in youR imageEs If you diddeNt view theM under florecent lIghitiNg but insteaD when outside?

I love st0rn (0)

Count (107594) | more than 13 years ago | (#2140568)

I have a st0rn ftp server with all sorts of kinky stuff!

Woah... (1)

dmccarty (152630) | more than 13 years ago | (#2140569)

At first glance, Battling Steganographyseemed like the title to a new Jurassic Park movie!

The news is not that bad (1)

Chakat (320875) | more than 13 years ago | (#2144387)

This only applies to an attack against one form of steganography, not the field in a whole. The incredibly ancient art of code words and hidden meanings will still continue as before, it just means that hiding bits in GIFs will have to get a little bit more clever. Probably the next generation of stego software will have built-in wavelet algorithms so that the program can automatically place the bits so that the wavelets won't be altered. This program is only 90% accurate, that means that one out of every ten imagaes with hidden bits don't set off an alarm. The only reason to get nervous is if the software is 99% accurate. 10% inaccuracy means that it's very easy to circumvent.

Statistical analysis? (2)

Balinares (316703) | more than 13 years ago | (#2158394)

There's that stenography tool, Outguess [outguess.org] , that claims it can hide info into a pic without changing the pic's statistical properties (entropy et al, I surmise). I wonder if it's Outguess that makes false (or misinformed) claims, or if Prof. Farid's research on statistical analysis is already out of date...

Personally, no matter what, I wish Prof. Farid a lot of luck. His work might be what will save our collective ass from SDMI-like schemes down the road.
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