Exchanging Pictures To Generate Passwords

Roland Piquepaille writes "Today, Ileana Buhan, a Romanian computer scientist, is presenting her PhD Thesis at the University of Twente in the Netherlands. She is using biometrics to protect confidential information when it is exchanged between two mobile devices. This is a very innovative approach to security. Buhan's biometric application will generate almost unbreakable passwords from photos taken by the connected users. Here is how it works. 'To do this, two users need to save their own photos on their PDAs. They then take photos of each other. The PDA compares the two photos and generates a security code for making a safe connection.'"

Comments

Oh Dear

[smallfries]

This sounds like interesting work as I'm sure that the hashing of the photos to generate the passwords is quite interesting research. But from the summary (on the uni site) the work is quite flawed as a security measure. If I see Alice and Bob taking pictures of each other in order to establish a secure link then all I need to do is photograph them both covertly and I can regenerate their password.

Re:Oh Dear

[arth1]

It doesn't work like that. From what I can tell, it uses the image as a seed.
This is secure as long as that picture is kept secure and NOT given to anyone else, ever.
However, given the nature of humans, that's too tall an order. If that picture ever leaves the phone on where it was taken, the security is broken.

Re:Oh Dear

[Anonymous Coward]

You just have to make a face for the picture that you would not otherwise make and no move covert photo-password stealing.

Perhaps a smile :-) would work.

Re:Oh Dear

[WarJolt]

Cameras can steal your passwords; Maybe theres some validity to what they say about cameras stealing your soul.

Re:Oh Dear

[Anonymous Coward]

What if the photo is based on Bob or Alice's genitals?

For many people (fewer every year it seems), this would be a pretty good way to ensure a secret picture.

Re:Oh Dear

[wvmarle]

Every image is different, it has quite some randomness in it overall. I'm no cryptographer but can imagine that randomness is suitable to make keys.

What this unfortunately does not seem to address is the secure exchange of those keys. Making a very large secure random key and having a strong unbreakable encryption algorithm is one, exchanging those keys in a secure manner is another. Secure as in having no way of a third party listening in undetected, and getting the actual keys.

In this case the users have to take photos of themselves, and of each other: that indicates they have to be close together. Then the whole key exchange issue is trivial as it can be handed to the other party on a memory card or cable link or whatever. It is more interesting to be able to exchange those keys over a distance, over an insecure communication channel.

Re:Oh Dear

[wvmarle]

Take the pictures for this purpose only and then delete them after making the keys, problem solved.

Re:Oh Dear

[Anonymous Coward]

The real advantage then, is for the Japanese. Because you won't know if they are exchanging information or just taking pictures.

Re:Oh Dear

[QRDeNameland]

Would that be pornometrics?

Re:Oh Dear

[ASBands]

An image is random enough, but you can take a cryptographic hash of anything you want to - a password, a phone number, a song, an image, etc. How many ticks the processor has made in it's lifetime or the total value of all the bytes added up (modulus something) currently in memory will also be quite random, so the "using a picture" thing isn't really solving any problems. However, it does provide the basis of a framework that would allow you to move that picture (along with the one of yourself) to other devices in order to keep the shared secret key so you can continue to verify the person you're communicating with, since you can re-generate that key. Although there was nothing preventing you from just moving a keyfile in the first place. Don't forget - the more places the key is, the easier it will be for attackers to obtain.

As for the secure transmission of those keys - it's called the Diffie-Hellman Key Exchange and it has been around for over 3 decades and remains unbroken. Alice and Bob communicate some numbers which allow them to generate the same key, but Eve has no way of generating the same number.

I also replied here, so if you think this post is unclear, read there, too.

Re:Oh Dear

[skaet]

I can see the problem there. Since this requires people to be physically with each other to take the photo it will be such an inconvenience when trying to share stuff over the airwaves (as is the case with mobile networks, not so much for the limited range of Bluetooth) they will simply keep the photos on the phone.

Phones also have incredible amounts of storage these days meaning people don't care if they take a photo and leave it since it doesn't affect anything. This easily defeats the fancy new security if anyone stole your phone.

Re:Oh Dear

[Toll_Free]

I agree with you, but see a flaw in your logic:

I would think the distance, white balance, color balance, etc. would all make a difference in the hashes generated. I mean, a difference of zoom levels on the two cameras, you taking a picture of "jane" from 4 inches away farther (or a quarter inch, depending on the resolution of the camera) could cause a completely different hash to be created (I would hope).

There is enough difference in each CCD or other type of camera to cause confusion in that...

Maybe not enough confusion to where another program couldn't figure out most of what was being hashed, but still..... It wouldn't be as simple, since I'm sure pixel placement would play a bit in the making of the hash.

Interesting... To say the least.

--Toll_Free

Re:Oh Dear

[Anonymous Coward]

Of course cameras steal your soul.

Proof: Paris Hilton, Britney Spears, Michael Jackson, etc. etc.

Re:Oh Dear

[fringd]

Secure as in having no way of a third party listening in undetected, and getting the actual keys.

if they are using PKE then they only need to know that the keys are not changed. it doesn't matter if the keys are simply overheard. the only keys transmitted are the public keys, which as their name suggests, are publishable.

You only need to worry about a man in the middle attack. It doesn't matter if anybody else hears you. You only need to know that you have gotten the key that alice transmitted, and not eve's key.

Now, none of this may really matter. TFA is extremely thin on the details, but the way they seem to be working it is this: they get some sort of fingerprint from facial pictures, -- something that won't change between one picture of a person and another picture of the same person -- and a pair of these fingerprints makes a key.

If this is really their plan, then none of this thread matters. As a reader pointed out above, Eve can just take her own pictures of Alice and Bob, and then eve can eavesdrop on their conversation as she will have their shared key.

Re:Oh Dear

[xous]

I'm not a cryptographer but this sounds exactly like a Diffie-Hellman key exchange except using photos to generate the key.

You would need still a copy of both photos to be able to decrypt the transmitted.

This assumes that the key-space used is large enough that a old fashioned brute-force isn't feasible.

Re:Oh Dear

[yvesdandoy]

Face pictures would be the public key and genitals ones the private one !

Problem solved. :))))))))))

Re:Oh Dear

[smallfries]

No you've completely missed the point. Each user takes their own photograph of themselves. This never leaves their device. When a connection is to be setup the other user photographs them. There are now 4 photos in the set:

Alice's photo of Alice
Alice's photo of Bob
Bob's photo of Alice
Bob's photo of Bob

Each user now has a pair of images that should be similar (but are not the same). Alice has a photo of her and Bob, Bob has different photos of Alice and himself.

The images are hashed in some sense to generate a seed for the key. The assumption is that the image hash is robust enough that the two different images of Alice generate the same seed, and the same for Bob.

So if I now take a third pair of pictures, one of Alice and one of Bob, and the hash is robust then I can recompute their seed, and derive their key. As I said originally, it's some interesting vision work to come with a robust hash like that, but it is not actually secure.

If you still don't believe me, then reread the article and consider that the security of the system relies on Alice's picture never leaving her device. The same applies for Bob. To perform key agreement that means the same seed must be derived from the separate images.

Re:Oh Dear

[V!NCENT]

Just let the devices make a picture of totally random crap and mix that with sound from the mic (anything it's pointed at when you hold it in your hand) and exchange it between devices. Then let the app on both phones exhcange it and hash it (the exact image is in pixels so there is no way one could ever make an exact copy of that picture and sound). This way it's just a purely random, pure text generator...

This way it's not any different from the current connecting proces somebody goes through when connection two bluetooth phones. They won't even have the idea that a picture and sound is being made. Ofcourse don't store the freaking picture on the phone and remove it emediatly from memmory.

I am sorry for the harsh comment but this is /.. You are supposed to have the inteligence to come up with this kinda stuff yourself.

Re:Oh Dear

[Sloppy]

Take the pictures for this purpose only and then delete them after making the keys, problem solved.

As soon as you put it like that, the improvements suggest themselves. Just get the key from /dev/random, and if you want to use the camera's CCD as one of the feeds into your entropy pool, great.

Re:Oh Dear

[Molochi]

ATTFA the whole thing is based on a visual biometric program that "recognises" (ie generates the same partial key) people even when there are minor changes to their appearance. So if I take your picture and you take your picture (or a third party takes your picture) that part of the key formula is the same. If a third party takes both of our pictures within the right parameters (probably a close up full face shot or perhaps using our Drivers Licence, passport, or mugshot photo), they should have the same full key generated.

The "better security" part just seems to be based on the idea that it is difficult to crack a long key and that during a later (non-face-to-face) transfer of data a random data thief wouldn't be able to get both photos.

Re:Oh Dear

[Anonymous Coward]

That'll work as long as long as the biometric program doesn't think they all look the same.

Re:Oh Dear

[gnud]

That was what I was about to say. This might be a convenient way of using one-time pads =)

Re:Oh Dear

[Molochi]

Facial Biometric programs usually try measure a bunch of things in comparison to the size of your face like the proportional length of your nose, the proportional distance from the tip of your nose to the corners of your mouth, etc...

There are composition rules you have to go by to get it to work. Like looking straight into the camera and presenting a large enough amount of detail to be scanned.

Of course there are other things that could be measured, like complexion or eye color, or your bottom row of teeth... or a retinal scan.

I think using this with phones that could make a retina print would be a pretty cool option. I don't know what resolution CCD you'd need for it but it wouldn't really be hard to do.

Re:Oh Dear

[Toll_Free]

So, basically, they have taken what I said above to heart, and already "fixed" it.

Not really being into Biometrics, thanks for the input. Makes sense now, and I can see how it could work.

--Toll_Free

Re:Oh Dear

[nizcolas]

I imagine most people would resort to going online for an image of genitals. I'd be willing to be a lot of users would have the first image that google returns as a search for: genitals, penis, vagina, etc

Re:Oh Dear

[BigJClark]

Obvious flaw, is what happens when Bob and Alice are unable to take photos of eachother? If they transmit them to one another, then Eve has a change to read this image. Of course, they could also create an SSH tunnel, to transfer the keys, but.. that.. would.. be... ahh nevermind, I'm sure its been hashed out numerous times already on this thread ;)

Standard problems?

[solafide]

How does can this deal with the standard picture-comparison problems - different lighting, different makeup, different facial expressions? If this works, this will be big for image-search, not just passwords, but I am significantly skeptical that it works as advertised.

Re:Standard problems?

[gsgriffin]

This doesn't appear to be analyzing the photo. If you look at the binary of the jpg image, it probably takes a sample of the code that comprises the image as a seed for the security. The statement appears to suggest that they must exchange the actual photo image. I take a photo of myself and then send it to you...I guess IR or bluetooth...Perhaps that's where the security could be hacked?

biometrics ?

[Anonymous Coward]

so where does the bio part come in ? a picture isnt bio anything
then again this another crappy Roland article so its not suprising its short on facts and long on plagiarism

Re:biometrics ?

[gsgriffin]

Biometrics is using something about you, your person, to measure or provide unique indentity. This is as much a biometric as a thumb scanner.

Been done before

[Anonymous Coward]

Johnny Mnemonic?

I seem to remember this is how the 'password' for the encrypted information put into Johnny's head

Re:Been done before

[MoFoQ]

and how they had to have this cyborg dolphin with cracking it...

so...if the dolphins go extinct....then it'll be secure?

Re:Been done before

[Anonymous Coward]

Cue sharks with frickin lasers to attack dolphins...

Re:Been done before

[MoFoQ]

or just hire a "canned tuna" company

Re:Been done before

[Thelasko]

I seem to remember this is how the 'password' for the encrypted information put into Johnny's head

Hmmm... I think I just figured out how to get my data through customs.

"and generates a security code"

[unity100]

"and generates a security code for making a safe connection ..."

and what if i eavesdrop that connection and duplicate that security code ?

Re:"and generates a security code"

[ASBands]

That's generally not an issue, as there are enough algorithms (such as the Diffie-Hellman Key Exchange) which can generate a secret shared key. These processes can be done at any time, over any channel and require transmitting around a kilobyte of information between Alice and Bob. Since this can be done at any time, what is the point of taking the pictures? Most of the key-agreement protocols are anonymous, so there is no good way to verify that Bob is actually Bob, which is what this intends to solve.

So, two users get together and associate the key which they make at the time with the photos they take of each other. The photos become the out-of-band channel that links Alice and Bob and allows for some level of authentication. This is basically a simpler solution to the key distribution problem we've already experienced with RSA - one that doesn't require a company like Verisign or a complicated "web of trust" solution. Alice trusts that Bob is Bob because Alice associated this shared secret key when she saw him AND she can see his picture when she receives the communication.

Potential hacks? Since we're talking about mobile phones, the retrieval of the shared secret key would be almost trivial if we came into contact with the device. Even if it's not, we can associate Bob's photo with someone else and masquerade as Bob. What if we don't have possession of the device? Well, then the vulnerabilities are the same as any other symmetric-key encryption system...and AES has yet to be broken.

Re:"and generates a security code"

[fatphil]

If this is like Diffie Hellman, which it probably is, then you can evesdrop all you like, you'll never know the shared secret key.

However, if you can _intercept_ communications, and act like a man in the middle, then you can pretend to be Alice to Bob, while appearing to be Bob to Alice. Straight DH has no defence against this attack, you need a additional authentication stage.

issues??

[thisisreallymyname]

this sounds well and good, but isn't it pretty easy to take a picture of someone else and some how fool this system?

Re:issues??

[gsgriffin]

If this was smart software designed to interpret an image, then getting a photo very, very close to the original might be possible, BUT this is an exachange of an actual photo. You must be standing next to the person at some point and give them via IR or bluetooth or SD or something, the actual image file that you are using. In some ways, it is just using some of the data of the photo file. It could have been a document, a song, or anything else. They just decided to use a photo, probably because it will be easy for you to identify and verify as the correct ID image...at least we hope you can.

Re:issues??

[edittard]

Or because it makes a better sounding headline, and (like any crap story) generates lots of comments and hence page hits.

Crack

[enbody]

Procedure: Alica and Bob have their own picture stored on their own phone. They each take a picture of the other so each has a picture pair (Alice+Bob) and construct a symmetric key from the picture pair.

Crack: Eve takes a picture of Alice and Bob to get a picture pair (Alice+Bob) and constructs the same symmetric key.

Re:Crack

[vux984]

Crack: Eve takes a picture of Alice and Bob to get a picture pair (Alice+Bob) and constructs the same symmetric key.

Why wouldn't it have to be using the same pictures that Alice and Bob took of each other?

Re:Crack

[gsgriffin]

Still missing it. It has nothing to do with who is in the picture. It has to do with the actual data in the file that stores the image. Put a badge on a person in a photo and the data of the jpg file will change. You could take 20 pictures of the same person standing in the same spot, and you will come up with 20 different files (binary code in the jpg, that is). This process only works by handing over the exact image file that you are using as your ID. If they don't have that exact image file, it wouldn't work.

Re:Crack

[vux984]

This process only works by handing over the exact image file that you are using as your ID. If they don't have that exact image file, it wouldn't work.

That's precisely what I meant. Alice and Bob don't even need to take pictures of eachother... they could just point and shoot in random directions, but there are clearly some convenience features inherent in using 'just taken' images of eachother.

Re:Crack

[Anonymous Coward]

Still missing it. ...

Yes you are still missing it. It has everything to do with who is in the picture. That's the whole point of biometrics. If you take 20 pictures of the same person you will end up with the exact same _biometrics_. Not the same files but the same biometrics.

Re:Crack

[Anonymous Coward]

Crack: Eve takes a picture of Alice and Bob to get a picture pair (Alice+Bob) and constructs the same symmetric key.

Yes, exactly. Talk about writing your password on your forehead.

Tags

[Naurgrim]

Johnny Mnemonic http://www.imdb.com/title/tt0113481/

Meh

[moniker127]

So if you take a photo of bob you ARE BOB?
This brings identity theft to a whole new level, its like how african villagers are afraid cameras will steal their soul.

No problem

[djupedal]

And since Ms. Ileana Buhan is on Facebook, we have her photo along with her friends...say 'cheese!'

Key change?

[aurelianito]

How do you change your key?
Option A: Hair cut.
Option B: New contact glasses
Option C: Facial surgery

This scheme seems to have the problem of biometric key schemes. As usual, how do you change a compromised key?

Re:Key change?

[Anonymous Coward]

As usual, how do you change a compromised key?

Easy, use a 12 gauge shotgun to randomize a new key.

Re:Key change?

[gsgriffin]

Take a picture of your dog. That would work. In any case, you still need to give the other person the image file of the photo you take. It has nothing to do with your skin and hair color. It the actual image file that must be on both ends. Just send out a new key, but not over the Inet.

Why am I...

[Forthan Red]

Why am I reminded of the recently invented Japanese cigarette machine, which used a camera and image analysis software to determine if the user is old enough to buy the cigs. Of course, it was easily defeated by simply holding up a picture of grandma in front of the camera.

What is the difference...

[Jane Q. Public]

... between this, and simply generating a shared key? Honestly, I don't see any difference. In effect, that is more-or-less what this does... generate a shared key for later communication. Big deal. It doesn't matter whether it is "biometric" at all... other than the fact that so far "biometric" data has been far easier to fool.

And the "SecureGrip" project is a joke. In order for anyone in their right mind to stake their life on a biometric security device for their gun, it would have to reject others almost perfectly, and accept the legitimate owner infallibly... the latter being the more important of the two by far.

We are nowhere near that kind of perfection. I wouldn't touch something that uses even the most recent versions of "SecureGrip" with a 10-foot pole, much less pay money for it.

Re:What is the difference...

[allen1]

These days you can take a photograph with almost every mobile phone. However, using this sort of photo to protect confidential data and send it safely is something new. Allen Alcohol Treatment

Re:What is the difference...

[noidentity]

I wouldn't touch something that uses even the most recent versions of "SecureGrip" with a 10-foot pole

I think it can tell the difference between a 10-foot pole and the owner's palm, unless the owner is a pirate with a hook hand (which, according to the MAFIAA, has been on the rise lately).

Re:What is the difference...

[Prof.Phreak]

...that is more-or-less what this does... generate a shared key for later communication.

Indeed. PhD worthy?

Re:What is the difference...

[jasmak]

I agree with everything said particularly about the SecureGrip project. In the Netforce book series by Tom Clancy, each agent has a special ring that they wear on their hand. And all guns will only fire if a valid ring is within a certain distance of the gun. I think that this will be the way of the future. Although it does not protect against stolen rings/guns, in the case that an officer drops his gun while fighting, the enemy cannot just pick it up and shoot.

Re:What is the difference...

[DrVomact]

I haven't really had time to study it, but as far as I can tell from the original paper (available as PDF from http://eprints.eemcs.utwente.nl/10783/) this is a user-friendly mechanism for creating a session key for two parties who are in close proximity. The key isn't supposed to be permanent. The security is provided by the fact that the picture of the other party is obtained through a "side channel" (i.e., light rays and not the channel through which the actual data exchange takes place—e.g. bluetooth). The seed for the key is obtained via some sort of biometric analysis that's "fuzzy" enough so that the keys will match for both pairs of images on both devices. There's no real security advantage over simply exchanging a key verbally on the spot—it's just easier than remembering a key and entering it on the device.

I'm big on privacy...but I can't remember the last time I exchanged data with anyone via my PDA or cell phone...other than actually making a phone call, I mean. Are there people out there for whom this is a solution to an actual problem, or is it just an academic exercise?

How awkward.

[Anonymous Coward]

It's going to rather embrassing when both users pick goatse for their photos.

Re:How awkward.

[Spy der Mann]

It's going to rather embrassing when both users pick goatse for their photos.

And a terrible security hole!

(I'm talking about using a duplicate famous picture, you pervs)

Almost Unbreakable?

[camcorder]

Why is that? If using random hashes make a password unbreakable then what's the ground breaking part of this? It's been known for decades that you need a very good random hash (and importance is proven with recent Debian comment-out code including gpg tools).

This application has some 'cool factor' since it would make your shoot pictures of your friends in order to protect your 'important' communication between them, but real problem in here is not hashing, it is password generation algorithm. If it has weaknesses your random hash (ie. salt) won't make it any secure. And also how applications reach/use this password is another factor.

Biometrics have a good 'cool factor' but they indeed put other problems into security. As other posters mentioned you can shoot picture of Alice and Bob, considering it uses facial information, you can mimic it. It is like you could get finger prints left on some fingerprint scanners. Besides libraries using those biometric data need to a lot more time to be proven as secure than textual password algorithm we use today.

I might be a conservative about this but I still believe that even though biometrics can put some additional security, they still need to be harvested with memorized (ie. textual or verbal) passwords. If you don't harvest them, then you add possible attack vector of biometric data encoder to underlying authentication stack code as well.

Re:Almost Unbreakable?

[Anonymous Coward]

Perhaps they are hoping that soon, cameras can take contact pictures using more than 20 Megapixels with 32-bit resolution uncompressed. With that kind of keys, maybe that will take some time to break. But then again, try not to use it under bright ambient light or really dark, because #00000000.... or #FFFFF... may be just to easy to crack.

'Static' pic may work better

[davidpfarrell]

[ I didn't RTFA ...]

Having to match-up two different facial pics seems like a possible point of failure - Both for false-negatives and false-positives.

Either you have advanced facial-pattern software to generate a 'fingerprint' from the pic, or you do something along the lines of downsize to 32x32 pixels, convert to black and white and hope for a 85+% match.

It might work better if you have to take a picture of something that is 'more guaranteed' to be the same every time.

For instance, a snapshot of your Driver's License pic seems like it might work (Just the pic, nobody wants their full DL floating around.

Hehe, no, a pic of the CELL PHONE itself!!

Even better, the cell phone could generate a unique bar code and you exchange pics of the code, or the cell phone and the code if you wish.

Re:'Static' pic may work better

[John Hasler]

> I didn't RTFA

You didn't miss anything. TFA is so content-free that it is impossible to tell what the hell this is about.

the greatest journalist ever

[ral8158]

Hi Roland! What's up? I haven't seen you in a while!

...seriously?

Twins???

[joocemann]

So... an identical twin, equipped with the technological veil of communications, can still break it? :D

Re:Twins???

[cailith1970]

It's only a problem if you're not the evil twin.

I preferred shake to sync

[aj50]

I preferred the shake to sync method where two phones would be held together and shaken randomly. Both phones take accelerometer measurements and use the pattern they were shaken in as a shared secret.

Re:I preferred shake to sync

[pclminion]

I just want to tell you how AWESOME that idea is.

Re:I preferred shake to sync

[WarJolt]

Both phones take accelerometer measurements

One step closer to Steve Jobs plan to dominate the world with iPhones.

Re:I preferred shake to sync

[Anonymous Coward]

Very cool idea, I agree.

Re:I preferred shake to sync

[Anonymous Coward]

yes :3 awesome, awesome idea

Re:I preferred shake to sync

[Aladrin]

The problem is synchronizing the accelerometers and getting them to take the same measurements. They aren't the most precise things in the world, and if you dumb down the data enough to sync them, you lose a lot of the security.

Re:I preferred shake to sync

[Sloppy]

If you're going to put the two phones physically together like that anyway, then why not just run a wire between 'em? Zipzip there's your OTP.

Re:I preferred shake to sync

[rsborg]

If you're going to put the two phones physically together like that anyway, then why not just run a wire between 'em?

That'd be great, 'cept I don;t know of an easy way to cable together two iPhones, or two Blackberries, much less between two different models/manufacturers.

The shake and bake shared secret is a great idea because it requires no additional connectivity. In fact the two devices can have NO network connection, but share only similar readings during an agreed time-window.

Accelerometers are only one way to generate "local data" that becomes a shared secret. Thermometers and other sensory input mechanisms that will (roughly) have the same readings in the same surroundings are also additional factors one can use to form the OTP.

Beside the point.

[Jane Q. Public]

Using a picture to generate the data may be new, but that doesn't address the difference between the data once it's generated, and any other shared key. I could as easily generate a key using a recording of my voice -- and that may be a new thing too -- but the end result would be exactly the same except for the particular combination of digits. Random typing could be used to the same effect (although it is a bit more difficult to get "random"-looking data that way). Or I could use heat noise from a reverse-biased diode or transistor.

Big deal. I am not impressed.

WTF?

[jcr]

What if they're not close enough to take pictures of each other?

Sorry, I just don't see the usefulness of this.

-jcr

Re:WTF?

[bronney]

Then you have an excuse to ask her to come closer no? I'd be in the basement.

Security challenge!!!!

[gandhi_2]

If you "lose" your picture, you can always "reset" your picture or have it emailed to you.

Just upload the following:

A picture of your highschool.

A picture of your first pet.

A picture of your first car.

Re:Security challenge!!!!

[hack slash]

"A picture of your first pet."


"Dad! where's the shovel?"

Exactly

[NotQuiteReal]

And if you do have to share a key in the open, just be obscure... like, "hey remember the first name of that girl we both [redacted*] at that beach party?" - that's the password to authenticate, "oh, and use the usual case and leet-substitutions..."

* not for salacious reasons, but just because I know the crowd here (hey, it could be "laughed at", "or felt sorry for", etc.)

And within 30 seconds on /.

[Secret Rabbit]

... it's completely broken.

So, who's this Ph.D. candidate and her supervisor? Because, I want names. I want to know who to stay the hell away from with regards to security.

WTF is the rotating circle thing?

[Anonymous Coward]

So what's the rotating circle thing below each article with a field you can type in, and a play button?!?

Off Topic

[s-twig]

She's hot. http://wwwhome.cs.utwente.nl/~balazsi/

Useless for Slashdot...

[Anonymous Coward]

> What if the photo is based on Bob or Alice's genitals?

This is why it won't be of any use to Slashdotters. Who wants to take the risk that they'll be sent goatse?

Sneakernet?

[chonglibloodsport]

If Alice and Bob are meeting in person, why do they need an elaborate key exchange protocol? Wouldn't it be easier for Alice to hand Bob a USB thumb drive with her key on it?

Sweet!!

[gparent]

I was looking for a new way to share these hot 2girls1cup vid caps!

Potential Failure

[robophilosopher]

And if you do have to share a key in the open, just be obscure... like, "hey remember the first name of that girl we both [redacted*] at that beach party?"

"Dude, I don't."

Why is this important?

[Anonymous Coward]

All that was done is this person swapped 'public' and 'private' "text-based" keys for image-based keys and generated a similar response. The input seed is much larger so I'm not even really sure what has truly been accomplished aside from the fact that any 8 year old with a camera can take a photo of themselves but apparently developing a security system where you tap your iPhone twice to generate an SSL Key is too difficult to come up with..or apple is shooting it down in the appstore.. eh..
apples and oranges, right?

U Twente

[Anonymous Coward]

I thought U Twente was just a huge warez server.

Guess I've been out of a long time.

Miss my shell there, and at RIT. :(

Haha

[Jane Q. Public]

I don't remember her name, but I do remember waking up with a Magic Marker in my hand...

Perhaps I'm missing something...

[ITEric]

Using biometrics means the actual pics need not be exchanged, but would they have to be taken from the same angle? Also, wouldn't an app sophisticated enough to do this accurately tax the limited memory of most mobile devices? As to security, assuming the would-be eavesdropper could tell that the salt was biometrically derived AND both knew and had access to pics of the people communicating, why would they bother to go through the trouble of cracking the encryption just to find out that so-and-so was seen necking with what's-his-name at a party?

Images as a seed

[jd]

That is a fairly poor way of generating a seed. I don't claim to be an expert on encryption (but you can call me one if you like), but I would use one of several different approaches, depending on the situation and the compute power available.

One option would be to assume that the two images are a pair of asymmetric keys, given some shared asymmetric encryption function which is derived once the two images are uploaded. It doesn't matter, then, if either image (but not both) falls into the hands of someone wanting to break the encryption - without knowing the function used, having what is effectively a private key for one side of the communication won't help.

A second option is to just use them as seeds for generating key pairs and instead of trading images, use an established method for key exchange to copy the keys across.

Thirdly, you could generate completely random key pairs, then use the photographs as part of the encryption mode between blocks. (This would go back to needing the photographs shared, but even if both photographs were obtained by someone, it wouldn't help them much in decrypting any message.)

Fourthly, you could generate a digital signature, where the signature assumes the image is appended to the message, with the signature as the first part of the encrypted message. This adds a little to the authentication, but also as the signature is non-deterministic, it makes those decryption techniques which involve some sort of pattern analysis of the encrypted data much less useful - you don't know where the text starts.

Next, you could use different slices of the images to pre-generate different keypairs. You could then specify a key by specifying the offset into the image. A variant of that is to pre-generate keys randomly and use the image content at a given offset as a pointer into the key table.

Lastly, you could prepend the message with the image, use a compression algorithm and then encrypt the compressed data. The reason for compressing is that it hides patterns in the data still visible when encrypted. By prepending the image, you absolutely drown out any possibility of residual information that could be used.

Re:Images as a seed

[genghisjahn]

Perhaps you should write a PhD thesis on this topic and present it...if you haven't already done so.

Re:Images as a seed

[huf67]

Well for somebody who doesn't claim to be an expert on encryption you've seem to throw out some 50 cent ideas about this...haha

Nothing is ever uncrackable...If a human thought it up...a human can crack it !!! With that being said we could start to let computers generate ideas about unbreakable encryption and never(as humans) know what they are doing. But then we may have to travel back in time to save John Connors one day !!!

Mod up! Mod up!

[Jane Q. Public]

Very cogent point.

Wrong

[fringd]

RTFA. who modded this informative? you should also RTFA.

from TFA:

...even if the user has altered his hair drastically, the system can still recognize him.

so this information IS the same if you take 100 pictures of the same person standing in the same place, or a different place, or if they cut their hair or put on a badge. the crack seems ludicrously easy.

Sadly TFA has extremely bare details. how did this become news on slashdot? I demand more details if I'm going to be bothered. Sometimes I think the admins put bad stories up just so that we can bitch about how bad they are.

Everybody missing what is important

[rossz]

It looks like everybody is missing the most important part of this article. The computer geek in question is a SHE!!!1!!!!~

We need photos.

Re:Everybody missing what is important

[Anonymous Coward]

http://wwwhome.cs.utwente.nl/~balazsi/

cute!

Re:Everybody missing what is important

[justinlee37]

"My research interests are in the fileds of protection of biometric information, coding theory and cryptography and secure spontaneous interaction." Misspelling hers. Maybe they don't have good spellcheckers in the Netherlands? Somebody should tell her to use Firefox or something.

Re:Everybody missing what is important

[Anonymous Coward]

It looks like everybody is missing the most important part of this article. The computer geek in question is a SHE!!!1!!!!~

We need photos.

http://www.inter-actief.utwente.nl/studiereis/kryptos/symposium/images/sprekers/ileana_buhan.jpg

Re:Everybody missing what is important

[Anonymous Coward]

here you go ;-)

http://www.inter-actief.utwente.nl/studiereis/kryptos/symposium/nl/sprekers/ileanabuhan

Re:Everybody missing what is important

[Anonymous Coward]

You're welcome.

http://www.inter-actief.utwente.nl/studiereis/kryptos/symposium/nl/sprekers/ileanabuhan
http://wwwhome.cs.utwente.nl/~balazsi/
http://www.linkedin.com/pub/1/489/a00
http://www.facebook.com/people/Ileana_Buhan/1253201571

google is great but i miss rapeleaf dot com

Re:Everybody missing what is important

[MoreDruid]

that wasn't so hard:
http://wwwhome.cs.utwente.nl/~balazsi/

Re:Everybody missing what is important

[rossz]

Hey, she's cute. I wonder if she would like to take advantage of a middle-aged American geek who has a weakness for Central European accents?

Re:Everybody missing what is important

[Anonymous Coward]

you're hired, you're hired, you're hired, you're hired!

Addendum

[Jane Q. Public]

Apparently, the big thing here is that later pictures can be interpolated by the software to approximate the original conditions: Party A's machine says "This picture looks like Party B", and Party B's machines says "This picture somewhat resembles Party A". Then it guesses that if the two are close enough, it should use the shared key that was originally generated.

Yeah, right.

This has all been done before. All it does is weaken any key that might have been generated in the first place, because rather than an exact match, it uses the legitimate key even when the imput is only "good enough"... and "good enough", given all kinds of biometric data, is anybody's guess. On the show "Mythbusters", they bypassed a very expensive fingerprint reader with an inkjet printer and some gelatin. It scored worse than a $35 USB plug-in fingerprint reader from the local computer store.

The point being that it less about the kind of data that you are gathering -- whether it is skin capacitance or resistance, or retinal scans, or fingerprint scans, or whatever. The real issue is not so much what data you have. The big thing is what you do with it.

This is the great weakness of biometrics. It has to be nearly perfect! Otherwise it is, like other similar measures, a "cure" that is worse than the "disease", because it is too easily spoofed. (See Bruce Schneier's explanations of the problems with biometrics and passport RFIDs. The concepts are very similar.)

Ms. Buhan's paper on the subject is available

[Anonymous Coward]

You can find it here:
http://eprints.eemcs.utwente.nl/10783/

She doesn't seem to be proposing using the image data for key generation directly, as a lot of people here seem to think, but instead to use biometric data extracted from the image. (facial features, for example)

If you're interested in reading more of her work, it's available here:
http://wwwhome.cs.utwente.nl/~balazsi/research.html

As an extra security layer

[mvanvoorden]

It might be a good idea to take a picture of Bob and Alice shaking hands, to be certain the handshake is secured, too. If there's proof the handshake really took place, you know you're connected to who you're supposed to be connecting with!

Roland Piquepaille has not proven trustworthy, IMO

[Anonymous Coward]

The problem is this is a Roland Piquepaille "story", and he is paid to get public relations pieces like this in Slashdot.

Just a variant of the one time pad

[Almahtar]

Right you are. This is just a one time pad. Its strength can be proven mathematically via information theory. To summarize, the strongest encryption is when the key is the same length as the plaintext, so a large key (such as a jpeg of a person) is inherently stronger than a smaller one.

As you correctly point out, the clincher is transferring the keys in a secure manner. If you're face to face with the other person you may as well exchange memory cards containing 2 gigs of data to use as the keys. Why settle for a ~60k jpeg?

Doesn't Work

[Anonymous Coward]

Okay, the thing is that the connection is made based on a biometric analysis of the picture taken. It is not taking a picture simply as a seed---there are better sources of entropy than that. Alice takes a picture of Bob, this is analyzed biometrically on Alice's PDA, on the basis of which a key is constructed that is compared with the biometric data of Bob's picture of Bob on Bob's phone, and vice versa.

To break this, get a suitable picture of Alice and Bob and you're done. You can however make it secure by using public key cryptography. However, this doesn't add much to standard security to public key cryptography, it only may add some weak authentification on the basis of biometric picture data. Anyway, judging from the stupid article I'd say it doesn't use decent cryptography and is entirely insecure.

Hi Roland!

[Anonymous Coward]

Isn't it sad to be you?

*eyeflutter*

[Anonymous Coward]

Johnny Mnemonic approves of this research.

I can..

[Anonymous Coward]

carry nearly eighty gigs of data in my head too.

Easy Problem

[Software Geek]

Manual key exchange between two people standing next to each other: So what?
Automated key exchange between people on different continents who have never met before: Now there's a problem!

The quality of articles on /. is decreasing

[jcookeman]

at an exponential rate. This isn't even PhD material. Yawn.

And what if...

[Jane Q. Public]

... the battery goes dead? Or an electronic component fails?

Maybe such a thing would be acceptable for the FBI, but I would not touch one unless it were absolutely reliable. Not 98% of the time, or even 99. Maybe if it were 99.99% reliable... 4 nines.