Apple announced on Wednesday plans to encrypt more types of data on its iCloud servers, including full backups, photos, and notes. The feature, called Advanced Data Protection, will prevent Apple from seeing the contents of some user data and make it impossible for the company to provide encrypted backups to law enforcement.

The encrypted backups will be opt-in and available in the US before the end of the year. Previously, Apple encrypted much of the data on its servers, but device backups containing text messages, contacts, and other data were not end-to-end encrypted, allowing Apple access to the contents of the backups. The move has been praised by security advocates, who previously criticized unencrypted iCloud backups as a weak point in Apple’s privacy policy. It also means that user data would not be exposed if Apple’s servers were ever breached.

However, the move may upset law enforcement, which has used Apple’s policy of not encrypting backups to obtain materials in investigations. Apple previously fought the FBI’s attempts to force it to unlock an encrypted iPhone used by a terrorist in San Bernardino. Law enforcement officials typically oppose encryption because it allows suspects to “go dark” and denies them access to potential evidence. Apple also announced two other security features on Wednesday: the ability to use a physical key as second-factor protection for Apple ID logins and the option for users facing significant security threats to confirm that text messages are not being intercepted.