ProtonMail, an email provider known for its focus on encryption, is adding a feature to its mobile apps that allows users securely store sensitive contact information.
ProtonMail’s “encrypted contacts” feature allows users to store contact information like phone numbers, addresses, URLs and other notes in the app, protected by the service’s “zero-access encryption.”
“Zero-access encryption” refers to the fact the only the user can access the encrypted information.
“All of this additional information is encrypted and no one but you can access it — not even we can access it,” the company wrote in a blog post.
In previous versions of ProtonMail’s iOS and Android apps, users could only store contact names and email addresses. This information is not encrypted, because it would prevent ProtonMail users from being able to send messages.
Even though names and email addresses aren’t fully encrypted, that information is protected with a digital signature. The signature makes it extremely difficult for an attacker to spoof those particular fields. Additionally, users get an alert in the event that an attacker does try to tamper with that information.
The Swiss company is known for its end-to-end encrypted email service, meaning messages can only be read if a user has a uniquely generated digital key. The service launched publicly in 2016, appealing to journalists, activists and any person looking to set up a secure line of communication.
ProtonMail made its encrypted contacts manager available via desktop in November 2017.