Using structured encryption to search protected photos in the cloud

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If they’re generating the meta data tags on the server, then the pictures aren’t meaningfully encrypted. There’s just no way.

Even on Boing Boing, it clearly states that meta data are generated on the users’ devices:

When someone uses Pixek to take a photo, the software performs machine learning analysis on their device to recognize objects and elements of photos, then adds tags to the image for each one. It then encrypts the image along with its tags, using a unique key stored only the user’s phone.

According to this, Pixek allows encrypted meta-data to be searched on the server, so you don’t even need the complete meta-data DB on the device.

Ooooh, interesting.

Having read TFA now, I think I get what they’re doing

  • locally generate meta tags
  • upload encrypted photo
  • upload encrypted mapping of meta tags to photos

So, the meta tags aren’t encrypted, but the links between a user’s photos and any meta tags they match, are.

Not entirely clear whether the user’s searches are done on the ciphertext, or the key is uploaded to allow links to be decrypted for search…

I’m all for systems that make it easy to securely store your photos. I’m a bit confused as to the need of a special meta-data search though. Why not just sync encrypted changesets to locally maintained databases? I am having a hard time imagining the metadata for the photos of all your friends and family taking up several gigabytes. Am I missing some use case?

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