Although WhatsApp has end-to-end chat encryption, this feature does not cover cloud backups that go into unencrypted state. The Facebook application states in the backup settings that "Messages and media created in Google Drive backups are not protected from WhatsApp end-to-end encryption."
But we did know that the company had been testing encrypted backups in the cloud for over a year, and after it was added to WhatsApp beta a few months ago, the new feature began to be available to everyone. 
From today, users of the application have the option to encrypt their backups end-to-end, before uploading them to Google Drive or iCloud. WhatsApp is of course proud that no other messaging service provides this feature to its customers.
Despite offering this feature that ensures that neither WhatsApp nor the cloud service provider can read your messages, encrypted backups of your chats are still an optional level of security. Of course, there are some things you need to know.
Backups can be encrypted end-to-end using a password of your choice or a 64-bit key. However, if you forget the encryption key, there is no way to restore the backups. Even WhatsApp will not be able to start this process, as it claims that it has no access to your key at all.
It also seems that this feature is being distributed gradually, as we do not yet have it on our devices. You can see Settings> Conversations> Chat Backup> Encrypted Backup if you can now.
