Also, Apple is woefully low on details, theoretical privacy should be accompanied by openly published research papers that are peer reviewed. I understand they won't release the source, but would you trust Apple if they said they invented a new encryption algorithm, but refuse to publish an academic paper on it? I'd be interested precisely in what they're doing. Are they claiming they're doing federated learning, by gathering anonymous image data from photos, uploading it to their cloud, training DNNs on it, and then shipping the results back down to clients for local recognition? Surely they're not training on device, as this is very RAM and CPU intensive.