AppleNeuralHash2ONNX VS Conversations

Perhaps you're referring to the hash collisions that were generated for the client-side NeuralHash which was reverse engineered about a year ago: https://github.com/AsuharietYgvar/AppleNeuralHash2ONNX/issues/1

Except Apple’s hashes have collisions where images that are similar in content but not identical will have the same hash. Meaning their process will have the same result: benign images being flagged as CSAM. See an example here https://github.com/AsuharietYgvar/AppleNeuralHash2ONNX/issues/1

perceptual hashes are completely broken due to false positives, like making a picture of a dog having the same hash as CSAM images. They are vulnerable to collision and have no preimage resistance, the most important feature. Because of that you can DOS conversations and people by sending dog images with the same hash as a CSAM: https://github.com/AsuharietYgvar/AppleNeuralHash2ONNX/issues/1

Specifically the fact that you can have one hash on two images, for example. There are other ways to abuse the CSAM system, which is confirmed by several researchers (one, two). And Apple saying it's not a concern... only to pull back on these plans.

AFAIK Conversations is one of the best, if not the best. On F-Droid it’s gratis, on Google Play it costs something.

Conversations (version 2.12.3): Encrypted, easy-to-use XMPP instant messenger for your mobile device

Had no idea Conversations got spun off?

Conversations [1] is the best Android XMPP client I know. IIRC they pushed the adoption of OMEMO and implemented it first, before the desktop clients could catch up.

[1] https://conversations.im/

Maybe have a look at Briar or good old Jabber (XMPP) with OTR or OMEMO, e.g. implemented in Conversations.

Conversations (version 2.11.0+free): An encrypted, user friendly XMPP instant messaging client optimized for mobile