"If the government laid a subpoena to get iMessages, we can't provide it," Apple CEO Tim Cook told Charlie Rose back in 2014. "It is encrypted, and we do not have a key."
Apple Stores Your Backup in Encrypted Form, But with its Own Key
Give the Encryption Keys in Hands of Users
How to Turn Off iCloud Backup on the iPhone
- Backup your personal data locally through Apple's iTunes.
- Turn off iCloud Backup. Go to Settings → iCloud → Storage & Backup → iCloud Backup.