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US District Court Says Calculating a Hash Value = Search
bfwebster writes "Orin Kerr over at The Volokh Conspiracy (a great legal blog, BTW) reports on a US District Court ruling issued just last week which finds that doing hash calculations on a hard drive is a form of search and thus subject to 4th Amendment limitations. In this particular case, the US District Court suppressed evidence of child pornography on a hard drive because proper warrants were not obtained before imaging the hard drive and calculating MD5 hash values for the individual files on the drive, some of which ended up matching known MD5 hash values for known child pornography image and video files. More details at Kerr's posting." Update: 10/28 16:23 GMT by T : Headline updated to reflect that this is a Federal District Court located in Pennsylvania, rather than a court of the Commonwealth itself.
This sounds like the worse possible way to search for kiddie porn, because a suspect who wanted to conceal his activities could just change a single pixel, and the entire hash would change. They would need a signature method that doesn't change dramatically when a single bit changes, like something based on a frequency analysis.
Palm trees and 8
The guy whose computer was searched, abandoned the computer and gave up any rights at that point, the person who found the porn was computers new owner. Just like any trash tossed out becomes public domain, there should have been zero expectation of privacy at that point. I am not a legal scholar, but I do not see how the 4th amendment applies here. It would be no different than if this was a diary in a different language and the person who inherited the diary found a translator, upon finding criminal evidence it would be fully admissible.
I will not be pushed, filed, stamped, indexed, briefed, debriefed or numbered. My life is my own.
"some of which ended up matching known MD5 hash values for known child pornography image and video files." Wait, so law enforcement has a database of kiddie porn and kiddie porn md5's? Some perverted bureaucrat found himself the right job.
"A claim for equality of material position can be met only by a government with totalitarian powers." Hayek
The problem I have here is I would think that this would come under reasonable cause.
Someone calling the police and saying "Hey I found kiddie porn on this computer." seems to be reasonable cause to me.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
Kiddie porn will be the new "baggie of drugs to plant on a perp." I wouldn't be surprised to see cops dropping usb drives on accidentally shot guys. "No, don't worry, I just planted kiddie porn on the guy. Disciplinary action? We'll probably get a medal for this."
;)
Or, a good excuse to turn a neighbor or family member in to the party. It wouldn't be hard for private citizens to plant evidence in that manner, either.
Incidentally, your tagline: "Ein Volk, Ein Reich, Ein Messiah." Is that an inept slam against Obama?
Actually, given that the Nazi's brand of national socialism was ideologically very similar to Soviet Communism in many ways, I think I prefer this.
"Ein Volk, ein Reich, ein Führer." -Adolf Hitler
"We are one Nation, we are one People." -The One 'leader'
Each character is a hex digit, not any alphanumeric, so it's 16^32=2^128 possibilities instead of 36^32. That's 186 billion times smaller, but it's still a lot.
Odds of one innocent file's md5 hash matching one identified file's hash md5 is insignificant. But in this case we are talking about and entire hard drive's worth of files compared to a database of all known digital kiddie porn.
Take a PC that has been in heavy use for a few years, you might have a couple hundred thousand files, each of which could collide with any of the hundreds of thousands (millions?) of hashes for every known kiddie porn related file on the internet.
Think of it like rolling dice. Rolling a double 6 on a pair of 6 sided dice is a 1/36 chance, but rolling any doubles is a 1/6 chance.
The odds of any single file on your hard drive matching any single file they have on record is significantly better than a specific file on your hard drive matching a specific file they have on record.
-Rick
"Most people in the U.S. wouldn't know they live in a tyrannical state if it walked up and grabbed their junk." - MyFirs
You have to set the bar somewhere, and then stick to it. Sure, you can be more lenient on edge cases, but you still need to say "the limit is X", or the whole legal system is a farce made out of "fuzzy rules we're kind of supposed to follow".
In particular, when we get to the 17-yo case, it's as simple as this: did you think, in good faith, that she was of age? If yes, you should be home free. We're talking reasonable doubt here. It's reasonable to think a 17-yo is 18 or 19. If it was publicized as kiddie porn in any way, I don't care if she's 15 or day shy of 18. You had the information available, you're screwed.
Actually, it looks like a pretty good search technique. It's fast, easy to automate, probably a low percentage of false positives, and can be used to link perps together through shared files. As you note, it would be easy for the pervs to block, by dropping a few bits, but I suspect it would be effective for a while.
It's still a search, with all that goes along with that. But it's probably better than having Officer O'Reilly deciding that your picture of your daughter playing at the beach sans diaper is porn.
I was taught to respect my elders. The trouble is, it's getting harder and harder to find some.
Indeed. There can be people with child porn on their machines who are totally innocent. ... and a myriad of other possibilities.
I can envision at least a dozen scenarios, including (but not limited to):
- Irate ex-wife planting the stuff.
- Refurbished drive which had only been deleted, not reformatted. Old stuff still (invisibly) in the \RECYCLER directory.
- Someone running a transparent proxy for their open wi-fi, to increase speeds and minimize the impact of sharing.
- Browser cache, where a remote site has put child porn in a sprite sheet or similar used to display ads. The user has never seen it, and thus not deleted it either.
- The user might be the rightful owner of the material, which is illegal only in other people's possession. A father having a picture of his own children, nude, will usually not be child porn. If someone copies the images and uploads them somewhere, they become child porn. But the original images aren't.
But that, or whether the guy is guilty or not is all besides the point, which is that without a warrant based on reasonable suspicion, no-one should have a right to inspect anything. The heinousness of the crime must never be allowed as an excuse to bend rules, or innocents will suffer.
Yes, easy, but many of the porn collectors aren't going to be bothered with actually doing the edit...
So, go out and make a program that will automatically change a few bits in each file in a directory. Make it a TSR, and watch for all files in a directory. Sell it, profit.
Then the fbi will be after your list of customers (child porn collectors) because it's more complete than theirs.
Shit, the FBI should write this program and sell it from a fake company.
Do not meddle in the affairs of sysadmins, for they are subtle, and quick to anger.
But the recent civil forfeiture provisions for copyright infringement they're trying to get signed (maybe already signed?) into law will allow them to do the same thing. The Feds can already seize your property on the mere suspicion that it is being used for illegal drug activity, and are not required to even file charges. When said seizure happens, the burden of proof is on the owner prove that it wasn't used for illegal activity.
The society for a thought-free internet welcomes you.
Or, just replace "victim" with "victim or legal representative of victim".
I don't think his point was that the victim needed to necessarily be present, just that the consequences should be compensatory, not punitive.
(Note: I am not endorsing his point of view, just trying to clarify his position.)
The creator of this post (Jacob Smith) hereby releases it, and all of his other posts, into the public domain.
These children that you speak of aren't some imaginary thing you can airly dismiss.
As a parent, I disagree. What's in the best interest of my daughter is growing up in a society that is free from the type of madness and baseless hysteria that forms the remainder of your post.
They are the hopes and dreams of the parents who raised them, the future of our society, innocent and worthy of our very best efforts to protect them.
Absolutely, and that includes remaining a society and not a festering mob. It includes not throwing out civil liberties and due process of law just to punish people we don't like. I don't like presidents that spy on Americans, and feel that it's in my best interest that Bush be brought to trial, but I don't see any slavering "conservative" mobs backing me up. It's much more likely that she'll live in a police state than she'll be molested by a stranger.
Honestly, I'd have to question the humanity of someone who is NOT outraged by any crime against a child
Who isn't outraged by this crime? But, that doesn't mean I can't be outraged if the perp's civil rights were violated, especially in this case. There are other shades than just black and white. How often have we read stories of people who went through "the system" for child porn that they could provide reasonable explanations for being there, such as malware? The law's priority IS to ensure the innocent aren't harmed...even if they've been falsely accused of having child porn.
That being said, pedophilia is a mental disorder that needs to be treated, not punished. I question the humanity of any person that can't see that some things can't just be wished, or locked, away and forgotten about.
and least we can understand now that, that, given the active choice to let child molestors walk, that, all this other so-called liberal talk about children is a lie.
Actually, it's the conservative churchies who are more likely to scream "think about the children" than the liberals. Despite what the Ministry of Truth (Fox News) tells you, "liberal" is not a dirty word. Liberals gave women and blacks equal rights. Liberals ensure that you, as a citizen, get a fair day in court. If, however, you're stinking rich, the 'pubs will be happy to bail you out...even if you ARE a child molester as lot of them have been found to be of late.
They aren't interested in trying to save anyone, not the working man or the children. They are a cancer who deliberately brings countries down and ruins cultures in order to secure power for themselves.
I thought you were talking about liberals here? This description matches the actions of the "conservative" party over the last decade and a half.
You just wait until Obama pardons Mumia
Having grown up in Philadelphia and having a fair number of relatives who serve on the Philadelphia police force, and the police forces of neighboring areas of New Jersey...well, I'm not going to defend Mumia...but I can tell you first hand that brutal racism is rampant in the people who are sworn to serve and protect in that area. My own family members and their friends on the force are sufficient proof to me. I know we like to live in a fantasyland where that's not true, but until you see it firsthand, you have no idea what you're talking about. But, given your other statements, that's not a hard argument to make.
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