What happened to the 5th? (encryption)

[birdman]

And how do you stop someone faking the hash after they modify the image.

Even assuming that there is a secret key in the camera, physical access to the camera is all you would need to be able to fake this.    Access to the secret key would be needed to validate the authenticity of the image anyway, so how do you protect the secret key from attackers while making it available to prosecutors?

You are correct, but my point was to show that an image in unaltered (as in, taken from a specific device, and not digitally modified).  With proper choice of the hash size, embedding method, and number of repeated steganographic blocks, you could be reasonably confident that some amount of the original data was present--thus any image with two set of data, or none, has been altered.  Ideally, the code would be based on a secure key exchange combined with a timestamp and unit ID.  Now, I am in no way saying these methods are absolutely reliable, but nothing is, it simply increases the likelihood of catching an alteration, or increases the cost of doing so (just like encryption). 
Film was just as alterable, it just was more costly/time sensitive to do so.

Now, a more important question, can anyone think of a provably secure method of making a digital timestamp?

[T.O.M.]

Maybe I jumped a point or two.  Right now, to authenticate a photo, or a video, or any recording, is to have someone testify that they saw the original, and the photo/video truly and accuratelly depicts what they observed.  It's then admissible.  All of this talk about hash and encryption means nothing at this point because the rules don't call for it.

And or more a concern are the digital records.  How hard is it to simply add or delete a line from a list of phone calls made by your phone?  A few keystrokes and no one knows the difference.

What frightens me the most about this is not that the police can fabricate evidence against me.  Heck, they've had the ability to do that for as long as there have been guys wearing badges.  It's the fact that the entire court system is sitting back and waiting for something to happen instead of looking at the new technology and doing something to the rules to protect the integrity of the system.

As to the OP, I stand firm on my opinion that compelling the password is a 5th Amednment violation.

[birdman]

Fabricate evidence?  No way man, people always die with crack sprinkled on them.

[RevDisk]

Rev,
You have just hit on some of the biggest fears of people within the justice system, be it criminal or civil, which is the ability of anyone to manufacture evidence that cannot be discerned from real evidence.  It's a real concern among judges and lawyers that in many situations, the advance of digital technology is putting the entire world of evidence in jeopardy.  No one uses film anymore, and digital photos are so easily manipulated that the value of photo evidence is starting to come into question.  Same for digital video.  You mention fingerprints.  Digital images of fingerprints are all the rage, and just as much a concern.  And don't get me started on all of the digital record keeping.

I know that teh trend around here is to fear the .gov using technology in this way, but it goes way beyond that.  Alter digital x-rays in a malpractice suit to get money from a doctor.  insurance company creates a set of digital photos or a digital video to use to deny your claim.  A candidate for office uses alterred digital photos or records to destroy the image of an opponent.  Piss off a neighbor, and suddenly he's got photos of you growing weed in your backyard, which he turns over to the PD, resulting in a search warrant that finds the weed he planted there.

It is truly endless, and frightening.  How does a court ensure that the evidence being offered is authentic, given the level of technology we have no, much less that which is just around the corner? 

You're not going to like this answer.  Really can't, when it comes to anything digital.  Oh, there's plenty you can do to make it better.  Maybe even within "reasonable doubt", too.  With escrowed hashes and strong crypto trusts (it's a PKI thing, like chain of custody but with crypto).  I wouldn't lay down money on it. 

All of the examples you mentioned are entirely possible, and have been done already.  I could certainly generate all of those.  With a bit of a hand, I could automate the process so YOU could do all of that as well by point and click.

Respectfully, you legal guys don't know the tech.  And the tech people don't know the law.  You'd need to overhaul a lot of legal procedures, and there's exactly nothing solid to replace them.  So, legal folks will try to pretend the situation doesn't exist, and apply outdated laws/procedures to digital situations.  This was my job for quite some time, actually.  Applying outdated Cold War laws to the modern society and technology.  And it'll work at least 80% of the time.  Course, that remaining 20% or less could be innocent folks going to jail on crimes they didn't commit. 

Ironically, the best methods for authentication come along with the best methods for encryption.  If a camera generates an appropriately constructed hash digest of the image, then encrypts that digest and imbeds it steganographically into the LSB of the image, there would be no way to remove it (if done appropriately), and it would provide a cryptographically secure way of ensuring the image is unaltered, as any modification would render the original hash unrecoverable.

Ah, implementation hack.  Sure the hash is cryptographically secure.  But where are ya storing it?  Unless it's an off-site and well secured escrow, you can mess with it by overwriting.  Remember, encrypted data should look almost indistinguishable from random data.  So even if you don't want to generate a new hash (which would be trivial), overwrite random sectors of the picture and your secure hash is now just random junk that proves nothing.

Quantum encryption is absolutely unbreakable.  In a theoretical world.  For the real world, I can give ya pictures of working kit that can intercept it without any evidence of interception.  Mathematical perfection rarely gets implemented so cleanly in the world, as we both well know.

[AmbulanceDriver]

Ummm...

Rev, that looks.....  Complicated.

[KD5NRH]

In pure theory, a search warrant is a court order, and failure to comply with the order could be contempt.

Wouldn't the warrant be an order only to the searchers?  IIRC, the subject is under no obligation to assist, merely not to actively hinder.  (i.e. you can't stand in the doorway to keep the cops out, but you don't have to unlock the door for them; the warrant just allows them to kick it in if you don't unlock it.)

Of course, with encryption, the issue boils down to who wants your data and why; the local sheriff trying to find your pirated videos isn't likely to dedicate the same effort and expense as NSA trying to get your list of Luxembourgish revolutionary spies who have been elected to the US Senate.  The sheriff may try the technical equivalent of a door-kick, while NSA does the technical equivalent of using ninjas with handheld backscatter xrays.

[RevDisk]

Ummm...

Rev, that looks.....  Complicated.

What does?  The quantum key exchange cracker?   Nah.  Not really.  I mean, sure it's complicated in theory, but pretty straight forward in electronic engineering.  Most of the hard work is done on FPGAs.  Everything else is really just getting stuff to and from the FPGAs.

The following is a bit simplified, so the physics geeks please don't smack me.  Quantum key distribution uses quantum mechanics to guarantee secure communication by using loophole in QM wherein any process of measuring a quantum system in general disturbs the system.  You're basically turning your standard PKI public key into photons, and relying on its quantum state for the information.  If you look at the quantum state, you change it.  You should be able to look at the qubits, do a bit of math and say "zOMG, someone iz readin' my qubits!" or "kewl, no one iz readin' my qubits".  Now, obviously, the quantum physics can't be cracked, but poor implementation CAN be.  If you say, do the math wrong, lazy or imcomplete.  Hence the above device.  So even using the most secure form of communication allowed by the laws of physics, you can still be screwed if you don't do it right.  

Heck, the hackers in question got it past the TSA.  Ponder that one.

[zahc]

You have just hit on some of the biggest fears delights of people within the justice system, be it criminal or civil, which is the ability of anyone to manufacture evidence that cannot be discerned from real evidence.

FIFY

All this is enabled and aggravated by the childlike faith and ignorance that people have in matters of computing. Cheap computing is the biggest invention in the history of mankind, IMO, but nobody knows how it works or understands the ramifications. If the geeks of the world were as ambitious as they are talented, they could literally inherit the world.

A great example; the average Joe still looks at the magazines in the checkout aisle at the store and thinks that they are photographs or that they represent reality in any way. They might, but there is basically no reason to believe that. The same Joe still believes in so many things that have been hollowed of all but the superficial by the proliferation of computing, networks, and data storage. The government is itself a victim (and an antagonist) in this as has been pointed out in this thread, with the very rule of law suffering under benevolent yet completely un-thought-out (or maybe perfectly thought out and malicious) march of technology for its own sake. I wonder how many generations must elapse, how many viruses have to propogate, how much must be extorted, how far the institutions of learning and law have to fall, before the masses revolt and refuse computing on any but their own terms. Society, government and corporations have already gone much farther than I would have imagined, and a higher price than I would have imagined has already been paid, all in a ostrich-like coping mechanism of pretending there's no problem. The early geeks from the shallow end of Moore's law saw this but were too optimistic, too utopic in their vision. The crypto-anarchic society is the only possible free technological  society. The other alternatives are amish-like luddism or a consensual slavery of those who wield the computing power and those who submit themselves to it. 

By the way, all this reminds me of my recent fingerprinting for my TX CHL. I put my hand on this little magic ansible thing, and it beeped, and my "fingerprints" were, according to the beep, in some database somewhere. "Fingerprints" which supposedly will be used in court of 'law' to decide guilt or innocence.

[Tallpine]

Cheap computing is the biggest invention in the history of mankind

Maybe not the biggest, but it ranks right up there with the pitchfork 

[KD5NRH]

A great example; the average Joe still looks at the magazines in the checkout aisle at the store and thinks that they are photographs or that they represent reality in any way.

You mean they didn't resurrect JFK to make Forrest Gump?