WhatsApp is piloting a new system that will allow users to access the app from a number of devices without using their phones.
Encrypted messaging service can currently only “mirror” app content stored on a customer’s phone to another device at a time.
To do this, the user has to scan a QR code on their phone, which means that it is impossible to do this when a phone is low on battery.
Using WhatsApp on a companion device can be slower and less reliable, and gets disconnected frequently.
But now the engineers at Facebook – the owner of the app – have come up with a system that allows customers to sync up to four devices with their WhatsApp account regardless of their phone.
The new feature will be rolled out to a small group of users as a beta test before being rolled out to all of its estimated two billion accounts.
In a blog post posted on Facebook’s engineering website, the company said it has developed new technologies to maintain end-to-end encryption while syncing data on additional devices.
The post said the main challenge has been to maintain security without developing new ways to store people’s private messages on its own servers.
Previously, each WhatsApp account was identified by a single identity key from which all encrypted communication keys were derived, according to the blog.
With the multi-device function, each device will have its own identity key.
Additionally, engineers were faced with the possibility that a “malicious or compromised” server would add devices to accounts that do not belong to the account holder to spy on their communications.
The blog said they overcame this by extending security codes to all of a person’s devices so that their contacts can always verify which devices they are sending messages to.
Finally, users will be able to see all the companion devices linked to their account as well as the date of their last use, and will be able to disconnect from them remotely if necessary.
Other security features include a new technology called “automatic device verification” so that devices can build trust with each other.
This means that your contacts’ WhatsApp accounts only need to compare your security code if you re-register your entire account, not every time you link a new device to it.
To link a new device to a WhatsApp account, customers will still need to scan a QR code from their phone.
The blog said, “This process now requires biometric authentication before linking where people have enabled this feature on compatible devices. “
He added, “Finally, people will be able to see all of the companion devices linked to their account as well as the last time they were used, and will be able to log out of them remotely if necessary. “