The White House wants to 'cryptographically verify' videos of Joe Biden so viewers don't mistake them for AI deepfakes

Depending on the implementation, there are two cryptographic functions that might be used (perhaps in conjunction):

• Cryptographic hash: An arbitrary amount of data (like a video file) is used to create a “hash”—a shorter, (effectively) unique text string. Anyone can run the file through the same function to see if it produces the same hash; if even a single bit of the file is changed, the hash will be completely different and you’ll know the data was altered.
• Public key cryptography: A pair of keys are created, one of which can only encrypt data (but can’t decrypt its own output), and the other, “public” key can only decrypt data that was encrypted by the first key. Users (like the White House) can post their public key on their website; then if a subsequent message purporting to come from that user can be decrypted using their public key, it proves it came from them.

The best way this could be handled is a green check mark near the video that you could click on it and it would give you all the meta data of the video (location, time, source, etc) with a digital signature (what would look like a random string of text) that you could click on and your browser would show you the chain of trust, where the signature came from, that it's valid, probably the manufacturer of the equipment it was recorded on, etc.

it would potentially be associated with a law that states that you must not misrepresent a “verified” UI element like a check mark etc, and whilst they could technically add a verified mark wherever they like, the law would prevent that - at least for US companies

it may work in the same way as hardware certifications - i believe that HDMI has a certification standard that cables and devices must be manufactured to certain specifications to bear the HDMI logo, and the HDMI logo is trademarked so using it without permission is illegal… it doesn’t stop cheap knock offs, but it means if you buy things in stores in most US-aligned countries that bear the HDMI mark, they’re going to work

For the average end-user, it would look like "https". You would not have to know anything about the technical background. Your browser or other media player would display a little icon showing that the media is verified by some trusted institution and you could learn more with a click.

In practice, I see some challenges. You could already go to the source via https, EG whitehouse.gov, and verify it that way. An additional benefit exists only if you can verify media that have been re-uploaded elsewhere. Now the user needs to check that the media was not just signed by someone (EG whitehouse.gov. ru), but if it was really signed by the right institution.

Adobe is actually one of the leading actors in this field, take a look at the Content Authenticity Initiative (https://contentauthenticity.org/)

Like the other person said, it’s based on cryptographic hashing and signing. Basically the standard would embed metadata into the image.

It needs some kind of handler, but we mostly have those in place. A web browser could be the handler for instance. A web browser has the green dot on the upper left, telling you a page is secure, that https is on and valid. This could work like that, the browser can verify the video and display a green or red dot in the corner, the user could just mouse over it/tap on it to see who it's verified to be from. But it's up to the user to mouse over it and check if it says whitehouse.gov or dr-evil-mwahahaha.biz

Probably you'd notice a bit of extra time posting for the signature to be added, but that's about it, the responsibility for verifying the signature would fall to the owners of the social media site and in the circumstances where someone asks for a verification, basically imagine it as a libel case on fast forward, you file a claim saying "I never said that", they check signatures, they shrug and press the delete button and erase the post, crossposts, and if it's really good screencap posts and those crossposts of the thing you did not say but is still being attributed falsely to your account or person.

It basically gives absolute control of a person's own image and voice to themself, unless a piece of media is provable to have been made with that person's consent, or by that person themself, it can be wiped from the internet no trouble.

Where it comes to second party posters, news agencies and such, it'd be more complicated but more or less the same, with the added step that a news agency may be required to provide some supporting evidence that what they said is not some kind of misrepresentation or such as the offended party filing the takedown might be trying to insist for the sake of their public image.

Of course there could still be a YouTube "Stats for Nerds"-esque addin to the options tab on a given post that allows you to sign-check it against the account it's attributing something to, and a verified account system could be developed that adds a layer of signing that specifically identifies a published account, like say for prominent news reporters/politicians/cultural leaders/celebrities, that get into their own feed so you can look at them or not depending on how ya be feelin' that particular scroll session.

TL;DR: one day the user will see an overlay or notification that shows an image/movie is verified as from a known source. No extra software required.

Honestly, I can see this working great in future web browsers. Much like the padlock in the URL bar, we could see something on images that are verified. The image could display a padlock in the lower-left corner or something, along with the name of the source, demonstrating that it's a securely verified asset. "Normal" images would be unaffected. The big problem is how to put something on the page that cannot be faked by other means.

It's a little more complicated for software like phone apps for X or Facebook, but doable. The problem is that those products must choose to add this feature. Hopefully, losing reputation to being swamped with unverifiable media will be motivation enough to do so.

The underlying verification process is complex, but should be similar to existing technology (e.g. GPG). The key is that images and movies typically contain a "scratch pad" area in the file for miscellaneous stuff (metadata). This is where the image's author can add a cryptographic signature for the file itself. The user would never even know it's there.

Rather that using a hash of the video data, you could just include within the video the timestamp of when it was originally posted, encrypted with the White House’s private key.

Apple's scrapped on-device CSAM scanning was based on perceptual hashes.

The first collision demo breaking them showed up in hours with images that looked glitched. After just a week the newest demos produced flawless images with collisions against known perceptual hash values.

In theory you could create some ML-ish compact learning algorithm and use the compressed model as a perceptual hash, but I'm not convinced this can be secure enough unless it's allowed to be large enough, as in some % of the original's file size.