QR Date – signed timestamps inside for verifying dates
qrdate.org
qrdate.org
NFTs are supposed to be an irrefutable, immutable record of ownership. But the only thing they can actually "prove" is the ownership of the NFT itself. It's like having a receipt that says "I own this receipt."
It's a similar story here: using a QR code is proof that at one point you got this QR code from qrdate.org, but it doesn't prove you didn't manipulate the image or video, in which case what value is it providing?
Back story: https://www.coindesk.com/markets/2017/06/26/proof-of-life-vi...
The block in question (open "Click to see more" and look for the "Hash" field): https://etherscan.io/block/3930000
An irrefutable cryptographic timestamp is just that, irrefutable.
Sometimes courts make mistakes, but you can’t expect any useful precedent over something like this.
Also, because of lack of expertise courts may simply not want to deal with this kind of proof and thus not acknowledge it.
Courts lack expertise on almost every subject, I don’t think this logic can actually hold up.
Opentimestamps cannot be bruteforced, and there are no keys that could leak.
Bruteforcing would require for you to permanently take over the entire bitcoin network.
In math, sure, but he specifically asked about a court of law. Irrefutable in math doesn't mean admissible in court. Then there's the 1, 6, 12, or however many random people that decide the case; they likely need the math explained to them, and two sides get turns convincing them the other is wrong.
> Irrefutable in math doesn't mean admissible in court
What is that even supposed to mean? Why would (relevant) math not be admissible in court? Do you even know what these words mean?
If cryptographic timestamps are relevant and not against the rules of evidence, obviously they are admissible.
The defence successfully argued that MD5 was not totally reliable -- even though the chance of it being faked was absolutely tiny.
The real irony was that without the MD5, the photos would probably have been accepted just on the police assertion of chain of custody.
(I've been looking for this news story but unfortunately I can't find it at the moment)
[edit- found it] https://www.schneier.com/blog/archives/2005/08/the_md5_defen...
In fact the MD5 was known to be vulnerable - maybe. But it's still the case that adding MD5 made it less trustworthy!
If the signature involves a hash of a bitcoin block we don't have to trust the site owner to not sign future timestamps.
It is still a concept as there's no implementation of it besides the tests in the repo, so it would require further refining for production apps. For example with specifying key exchange formats, which we are looking at right now. Anyone with expertise in this field wanting to contribute is welcome!
The point of this website is that the server signs the timestamp. It's more than just a QR code with a time and date, it has some actual verification code.
the website has the exact same problem that you pointed out for the blockchain: you can screen capture a QR code and re-use it later.
Right on the page, it says this.
Maybe I am not understanding your point. Both the website and the blockchain strategy make it impossible for you to record video content and claim it happened in the future, but neither of them defend against recording after the timestamp happened.
The blockchain strategy does not require a centralized service, while the QR code requires the website to be up forever.
There's also a way to generate the codes offline using a certificate chain and a fingerprint (https://github.com/qrdate/qrdate#static-qr-date-v1-spec) which does not require a website, just a key store. It needs more specifying to be viable for real world use but it should be possible. Help is very welcome.
AFAIK, signing off a timestamp and offering a public key to prove the timestamp was signed then doesn't seem to add value other than unnecessary complexity. I guess if there is a specific time you're trying to prove the event happened after, this system would offer higher fidelity than others, but not all.
Nothing, which is amusing irony.
Using info from the the block is safer as you don't need to trust the host of the system.
The point (like showing a newspaper) is to prove the image / video was taken no earlier than that time.
That thought does does cast an additional possible funny interpretation on a photo I took of the adjacent street newspaper vending boxes of the two major Boston papers one day. The Boston Globe main headline was of a serious major news event. The Boston Globe above the fold was mostly filled with a photo of some political or sports figure, and a lowbrow muckraking headline about them. A funny (highly implausible) theory is that the Herald editor/publisher had needed to determine the front page for a paper issue, days or more into the future, such as for faking proof-of-life on/after a date, and then had to run that front page. :)
It always only proves that it wasn't taken before a certain date.
You can then also prove "not after" by timestamping the picture (having it signed by a RFC3161 timestamping authority or putting a hash on the blockchain).
https://github.com/QubesOS/qubes-secpack/blob/master/canarie...
edit: and the script itself: https://github.com/QubesOS/qubes-secpack/blob/master/utils/p...
As it says, I can use a code from today and add it to a video from yesterday.
I don't know who controls the private key, so how can I trust that they won't sign tomorrow's timestamp today?
If someone scans the code, and visits the website, their IP and UA will be logged. Which is a good way to track who has viewed your video.
These are all valid concerns.
Programatically superimposed usage of the code is problematic for all the same problems as with EXIF manipulation, so the thinking is to recommend using a physical prop (smartphone or paper) that makes it harder to fake the code in later. When combined with rapid distribution (to a news agency, live feed, Telegram or such), there's a period of time where I think it's unfeasible that someone would had tampered with it to future-date an older image.
It is possible to superimpose the code of course, as I noted:
"For example, when uploading photos through a messenger service, the service can sign the photos upon upload date and superimpose the QR Date onto it. Any further uploads to date the photo again would have to either crop the code out or otherwise mangle it so much that it would raise suspicion.
For videos, the QR Date can be superimposed as either moving around in the frame, switch places, or other motion to make it harder to superimpose another code later."
However these would only be indicative, not definite proof, and would need to be combined with other efforts- mainly deduplication, to find doubles.
For key storage and logging, I don't think it's my job to try to convince people to trust me with a private key (or logs) for the purposes of introducing this idea. Frankly I do not want the responsibility. If it ends up being useful, I would be happy to donate the domain to a reputable NGO or journalistic organisation for proper storage of the private key on a hardware device, contracts on how it and logs are handled, etc. In the meanwhile, if you want to trust the site, it's up to you just like with any CA.
I don't think a single online centralised authority would be a good idea in any case- it's why I'm trying to also consider situations where it can be used offline and by many organisations that each have their own requirements for trust.
Some notary services allow you to inject documents or hashes into cryptocurrency blockchains which prove that the submitted documents existed before a timepoint.
Not with what GP proposes.
If I understand their proposal correctly, it is to include a value from "the current-highest-block from a blockchain to incorporate proof of a previously-unknowable, globally-verifiable value." You can always include historic values trivially.
It is much more involved to actually do a transaction on that chain, which could indeed be used to prove existence before a certain time. But yes, your alternative proposal would work for that, if you assume the chain cannot be controlled by any individual/partisan party.
This smells like complete bullshit to me. You can incorporate a QR code like this into any image whatsoever.
To prove "beyond a reasonable doubt" that an image was taken at a certain date, or not before a certain date, you need a trusted witness who saw it being taken, who signs the entire image.
All you know is that neither the image nor the code came from the future, which is self-evident.
I suspect the idea here is to rely on it being difficult to forge a printed version of the QR code that is shot together with the scene. For that purpose, a newspaper is better; it is more complex. I mean, someone could take a picture in, say, the year 2032, using a new QR code (printed on paper and everything), and then carefully edit an old QR 2022 QR code into that image. It's a very regular, high contrast, simple image.
In the era of deep fakes, I can't believe someone would think any of this is "beyond the shadow of a doubt".
I don't think anyone has said "beyond the shadow of a doubt" besides you. Reasonable doubt is a different thing. If you wanted more veracity, you could always keep on taking more pictures around the subject with more codes, or just keep holding the generator within frame for video.
The news article headlines get cut off pretty quickly to the effect of "Putin [says something]", but I guess it's not overly important as long as the headlines differ in wording.