Apple’s Craig Federighi was interviewed by Wired about the company’s Private Cloud Compute infrastructure that will handle Apple Intelligence requests that can’t be handled locally on-device. Federighi told Wired’s Lily Hay Newman:

What was really unique about the problem of doing large language model inference in the cloud was that the data had to at some level be readable by the server so it could perform the inference. And yet, we needed to make sure that that processing was hermetically sealed inside of a privacy bubble with your phone. So we had to do something new there. The technique of end-to-end encryption—where the server knows nothing—wasn’t possible here, so we had to come up with another solution to achieve a similar level of security.

Still, Apple says that it offers “end-to-end encryption from the user’s device to the validated PCC nodes, ensuring the request cannot be accessed in transit by anything outside those highly protected PCC nodes.” The system is architected so Apple Intelligence data is cryptographically unavailable to standard data center services like load balancers and logging devices. Inside a PCC cluster, data is decrypted and processed, but Apple emphasizes that once a response is encrypted and sent on its journey to the user, no data is retained or logged and none of it is ever accessible to Apple or its individual employees.

PCC is a complex system that leverages technologies that Apple has developed like the Secure Enclave, Secure Boot, and Trusted Execution Monitor to ensure customer privacy. Those technologies are backstopped by making every PCC server publicly available for inspection and verification by third parties. That said, Wired spoke to security researchers and cryptography experts who told the publication that although PCC looks promising, they hadn’t spent significant time studying it yet.

Cloud-based privacy is a tough problem to solve. I’m keen to hear what independent researchers think of Apple’s solution, once they’ve had more time to evaluate it. If PCC is as robust as Apple claims, it’s the sort of thing I could see Apple turning into a standalone product as worldwide regulation pushes tech companies to offer better privacy protections for their customers.