Yes, WhatsApp messages are encrypted using end-to-end encryption. This means of security ensures that every communication on WhatsApp stays between the sender and recipient of the message. That way, no third-party individual or organization can access the messages while it is being sent.
Not even WhatsApp or Facebook, which is WhatsApp's parent company, can access the content of your communication. This encryption method works hand in hand with the Signal protocol encryption. Signal protocol protection uses cryptographic keys or, as WhatsApp calls it, private keys.
Private keys are unique identity keys that are needed to decrypt a message sent through WhatsApp. However, this will be impossible since no third party has access to these keys.
But in the bid to expand users' options of companion devices that can be used to access a WhatsApp account, a multi-device architecture was also added to the encryption procedure. Each device has a specific private key that WhatsApp account owners can use to list their different devices. To verify a new device, you will need to scan the QR code for that device.