"Encryption for us is the same in every country in the world...We worked with a Chinese company to provide iCloud, but the keys [...] are ours...I wouldn't get caught up in 'where's the location of it,' I mean we have servers located in many different countries in the world. They're not easier to get data from being in one country versus the next...The key question is how does the encryption process work, and who owns the keys — if anyone. In most cases for us, you and the receiver [of a message] own the keys." - Tim Cook
(https://www.businessinsider.com/tim-cook-apple-encrypts-data...)
Apple is specifically stating that they have retained control over the encryption keys.