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Anamorphic encryption against dictators - hiding message inside normal looking ciphertext (eprint.iacr.org)
submitted 1 year ago by to c/privacy@lemmy.ml
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I want to share an interesting cryptography paper which introduces "anamorphic encryption", where the ciphertext encrypts two messages. One is a message to reveal to a dictator, who wants the secret key and message to control the narrative. Behind it lies a hidden message, guarded behind a "double key", which is to communicate messages of intent secretly.

It's kind of like having a duress key to reveal, but instead you can send real messages with the real key.

For instance, an investigative journalist could encrypt a fake message "Everyone is content in our utopia" as a smokescreen to show to the dictator, while true messages like "Minorities are forced into labor camps" can be hidden in the anamorphically encrypted ciphertexts to notify the outside free press.

The authors argue that cryptosystems already in use supports the anamorphic mode, where you encrypt a normal-looking ciphertext which contains the hidden message.

Given that it has been 3 years since this paper, I think there would have been some applications of this technology. Do you guys know of any?

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[–] 4 points 1 year ago* (1 child)

I posed this in another 'obfuscation' thread, but in the case of steganography, wouldn't AI have the ability to 'see' that the a file, say a image' has odd bits in it that shouldn't be in an image? Even further, would it be able to ascertain that you have two levels of messages hidden inside the image? It sounds similar to what you can do with VeraCrypt Cryptomater in that you have two 'levels' of encrypted data. One to reveal to the authorities and one that's for the intended target of the data packet.

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  • [–] 2 points 1 year ago

    That's if you are using a file to store additional data. Also JPEG and other lossy formats can have all sorts of artifacts that may (depending on the size of hidden data) seem typical.

    What I thought they were referring to was encryption at the filesystem level which doesn't require file blocks to be contiguous, allowing blocks to be interlaced with the hidden data.

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