Until now, WhatsApp has lacked the capability to store contacts within itself, relying instead on iOS and Android"s default contacts app. For example, to add someone to your WhatsApp list, you first had to save their name to your phone"s contacts. This is finally changing with the new Contacts feature in WhatsApp.
This feature allows users to save a contact exclusively to WhatsApp. This is useful for users who want to separate personal and business contacts when managing multiple WhatsApp accounts on their phones. Additionally, since WhatsApp is no longer dependent on smartphone OS contacts, you can now add and manage contacts from the WhatsApp Web and Windows experiences.
Furthermore, these WhatsApp-exclusive contacts can be restored if users lose or change their smartphones. The WhatsApp team highlighted that this new Contacts experience will eventually enable users to manage and save contacts by usernames. Usernames on WhatsApp will eliminate the need for phone numbers when messaging someone. WhatsApp will share more information on username support in the future.
To allow users to save their contacts and automatically restore them directly through WhatsApp, the WhatsApp team developed a new encrypted storage system called Identity Proof Linked Storage (IPLS).
IPLS allows the client device to save contact information using a strong encryption key generated on the device. Retrieval is based on the client authenticating its primary device identity. IPLS is based on two existing technologies already used at scale by WhatsApp: key transparency and their hardware security module (HSM). To further ensure the safety and security of this system, WhatsApp partnered with Cloudflare to provide independent third-party auditing of its cryptographic properties.
You can learn more about the new IPLS system from the WhatsApp team here.
This update marks a significant step towards greater privacy and flexibility on WhatsApp. With the upcoming username feature, users can look forward to even more control over their messaging experience.