[RcouF1uZ4gsC]

Was there discussion about the downsides of open sourcing the implementation? With an open source implementation, it becomes easier to test transformations that will change the hash without changing the image in ways a human can’t notice?

[faustomorales]

Great question -- all of the hashes we included in the package have been public for years (except for PDQ, which was open-sourced this year). So this package doesn't reveal anything new with respect to the algorithms themselves. What we add is an easy path to using at least one of them for the CSAM hashing / matching use case. Non-public perceptual hashes for this use case exist and, naturally, are not available in the package.