Since a long time now, people have been putting forward their request for a true multi-device experience that allows them to use WhatsApp on other devices without requiring a smartphone connection.
In response to their requests, the launch of a limited public beta test for WhatsApp’s updated multi-device capability has taken place. This feature allows you to access WhatsApp on your phone as well as up to four other non-phone devices at the same time, even if your phone’s battery is dead.
Each companion device will connect to your WhatsApp independently. The level of privacy and security that WhatsApp users have come to expect through end-to-end encryption will not be compromised ny any means. Infact the newer technologies allows to maintain end-to-end encryption while still syncing your data (such as contact names, chat archives, starred messages, and more) across compatible devices.
The current user experience enabled through a synchronisation of a phone device with companion devices has a set of some significant reliability trade-offs, which is seemingly being looked upon through the new tech architecture to be launched soon.
The first trade-off is that all operations must be performed by the phone, companion devices are slower and frequently disconnected — especially when the phone’s connection is poor, its battery is running low, or the application process is killed by the phone’s OS.
It also allows only one companion device to be active at any given time, so people can’t be on a call in Portal while checking their messages on their PC, for example.
The new WhatsApp multi-device architecture eliminates these barriers by eliminating the need for a smartphone to be the source of truth while still keeping user data seamlessly and securely synchronised and private.
Various concerns related to this new feature
The issue of preventing a malicious or compromised server from listening in on someone’s communications by secretly adding devices to someone’s account, has been already overcome. There are extended security codes to now represent the combination of all of someone’s device identities, allowing anyone and their contact to always verify all of the devices to which they are sending messages.
Second, a new technology has been developed and will roll out, which is called Automatic Device Verification to reduce the number of times someone must perform identity verifications.
This system enables devices to automatically establish trust with one another, so that someone only needs to compare another user’s security code when that user reregisters their entire account, rather than each time they link a new device to their account.
A final aspect is that people get more control and security over which devices are linked to their account. To begin, everyone will be required to link new companion devices by scanning a QR code with their phone. Where people have enabled this feature on compatible devices, this process now requires biometric authentication before linking. Eventually, people will be able to see all of the companion devices associated with their account, as well as when they were last used, and will be able to remotely log out of them if necessary.
WhatsApp server securely stores a copy of each application state that can be accessed by all of a user’s devices. To ensure proper security, all information, including metadata about the information (such as what type of user data is stored or accessed), is end-to-end encrypted using constantly changing keys known only to that person’s devices.
How to Test the WhatsApp Multi-Device Beta
The beta feature testing will begin with a small group of users and will continue to optimise performance as well as add a few new features before gradually rolling it out more broadly. Those who opt in have the option to opt out at any time.