WhatsApp announced on Friday that it would add an end-to-end encryption option to users' backup messages.

Facebook CEO Mark Zuckerberg made the announcement in a Facebook post, saying that the end-to-end encryption option will store your backup messages in Google Drive or iCloud.

"WhatsApp is the first global messaging service of this scale to offer end-to-end encrypted messaging and backup. Achieving this was a major engineering challenge that required an entirely new framework for key storage and cloud storage across operating systems," Zuckerberg wrote in his Facebook post.

A whitepaper describing the new feature, published Friday, notes that WhatsApp users will be required to store a 64-digit encryption key or create a password when saving their encrypted backup messages. Additionally, end-to-end encrypted backups will only be supported on a user's device.