The end-to-end encryption feature of WhatsApp enables the chats between the sender & receiver to remain private. It is found that when WhatsApp data is backed to Google Drive or iCloud, the backup is not encrypted which means that a search warrant can be issued by authorities to ask these clod companies to hand over the data & they would have to including WhatsApp chats that are not protected by encryption. However, there are rumors about technology being developed that would encrypt Whatsapp backups on drive. This system is enabled on the latest WhatsApp update on Android- version 220.127.116.11. A beta testing is being performed on this feature. Such encryption would require a password or 64 digit recovery key that would help in restoring the password. Whenever a user wants to restore the backup from the cloud they would use this password or recovery key. The key point in this is that the password or the key would be unknown to even WhatsApp, Facebook, Apple, or Google. Only the user would have the access to this backup data which would be lost in case the user forgets their password or key. This feature is in its testing phase after which it would be determined whether it would be rolled out. This feature would keep the WhatsApp chats & data private in spite of third parties like the cloud being involved.
Source: Financial Express