> The digital images can be converted to binary data and encrypted with Advanced Encryption Standard (AES). However, the high correlation between adjacent pixels may still be kept after encrypting a digital image without considering the property of digital images.
What do you mean by this? It sounds like it’s suggesting that, e.g., the AES-CBC ciphertext of an image has detectable internal correlations. In other words, AES is completely broken as a cipher. Surely I’m misinterpreting the claim here.
Yeah, this paper is a good representation of the whole "chaos cryptography" theme — snake oil cryptography invented by authors who don't even attempt to study cryptography before producing their bullshit and publishing it in sketchy or generalist, unrelated to cryptography, journals.
In this particular paper:
1. The motivation for "image encryption" is completely wrong, as you pointed out.
2. There is no secret key. The "key" is produced by hashing the image with SHA-256.
3. Claim: "No any useful information can be acquired from encrypted images". Actually: since this is convergent encryption (https://en.wikipedia.org/wiki/Convergent_encryption, "key" derived from SHA-256 of data), encrypting any two equal images will produce the same ciphertext, globally.
4. Finally, the actual "key" can't be more than 64 bits, since SHA-256(image) is then split into two groups of 32-bit words, which are xored together to produce two key values. Thus, this whole "encryption" scheme is limited to 64-bit security (probably even less than that). We don't even have to analyze the whole "chaos" system they invented to conclude that it's insecure.
I guess they’re referring to AES-ECB, which is notoriously weak at encrypting images (it’s weak in general of course, just most obviously with respect to images): https://words.filippo.io/the-ecb-penguin/.
But I don’t think the same is true of the other AES cipher modes.
> The digital images can be converted to binary data and encrypted with Advanced Encryption Standard (AES). However, the high correlation between adjacent pixels may still be kept after encrypting a digital image without considering the property of digital images.
What do you mean by this? It sounds like it’s suggesting that, e.g., the AES-CBC ciphertext of an image has detectable internal correlations. In other words, AES is completely broken as a cipher. Surely I’m misinterpreting the claim here.