Comment Comment by Retr0id > we sign a perceptual hash (pHash) of the image rather than an exact pixel checksumPerceptual hashes are non-cryptographic. There are certainly collision attacks, but what about preimages? A preimage would completely break this scheme.This paper demonstrates second-preimage attacks against PhotoDNA and PDQ: https://eprint.iacr.org/2021/1531.pdf parent Retr0id 2 months ago
Perceptual hashes are non-cryptographic. There are certainly collision attacks, but what about preimages? A preimage would completely break this scheme.
This paper demonstrates second-preimage attacks against PhotoDNA and PDQ: https://eprint.iacr.org/2021/1531.pdf