With Signal you can now choose that messages from unknown numbers must first send a contact request. The same goes for adding a person to a group. The contacted user can then choose whether to allow, block or delete the request.
If you make a request, you release your profile. Like all messenger messages, this information is end-to-end encrypted. As usual, the metadata on who communicates with whom is not collected. As an open source messenger, Signal has focused on protecting the privacy of users.
Profile instead of phone number
For new group chats, the messenger now also shows the profile information, even if the other users are not yet in the contacts. Previously, the phone numbers of strangers could be viewed. A procedure that the Messenger Telegram had already fallen on its feet because demonstrators in Hong Kong could be exposed by the authorities. Telegram then changed the visibility, since then you can also hide the phone number.
Signal will in future indicate that someone is saved in their own contacts with an icon next to their name. If you change your profile information, this appears directly in chats. In the case of voice messages and video calls, non-contacts must first make a request. Signal explains in a blog post
that in such a case no phone rings are received.
Signal recently introduced a PIN function, which was not met with much enthusiasm by critics, as it would save more data on Signal servers – these may not be adequately secured. The PIN should make it easier to restore accounts, i.e. profile, settings and contacts, when switching devices. This information can therefore be encrypted or decrypted with the PIN selected by yourself. Messages are explicitly not included. In the longer term, the PIN should also help to further strengthen anonymity by making the disclosure of the telephone number obsolete.