Signal is Looking at Adding an Option to Sign Up Without a Phone Number

References in Signal's source code point to a new feature to sign up without giving a phone number, potentially requiring a one-time payment.

Signal is one of the most popular encrypted messengers on the market and is regarded highly by privacy advocates the world over. But one of the major sticking points that turns people off signing up is the phone number requirement.

Phone numbers are personal information that can link your accounts back to you. Many countries have Know Your Customer (KYC) laws that require you to give personal information when you sign up for a new phone number.

Even when it's not required by law, many carriers collect troves of personally identifying data anyway when you sign up.

Signal added Phone Number Privacy as a feature to hide your phone number from other users by default and added Usernames that you can set that will allow other people to contact you without a phone number, similar to how many websites have user-settable usernames as identifiers just for that service.

Even with these improvements, a phone number is still required to sign up. In a blog post from 2023, Signal estimated that they spend around $6 million dollars per year on verifying phone numbers.

Signal CTO Ehren Kret said responding to a question at FUTO's Don't Be Evil conference:

"that is something we are looking a hopefully for later on this year adding a way to sign up without phone numbers. Uh the main uh downside at the moment and the reason we don't have that yet today is removing accounts who are are spamming people or otherwise engaging in abuse of the service is sort of our our primary way of protecting people from spam and other sort of issues like that that would affect the operational stability of the service."

While this confirms their interest in phone numberless signup, it doesn't give any solid confirmation that it will happen.

About Signal spotted several commits on Signal's GitHub with commit messages that reference accounts with no phone numbers, such as "Don’t allow or set registration lock on accounts with no phone number," heavily suggesting that Signal is actively working on a feature allowing you to sign up without a phone number.

Kret mentioned in the Q and A video that phone numbers introduce a small cost that helps prevent spammers from making loads of new accounts, so a new replacement would need to similarly add a cost to prevent spam.

More references in Signal's source code suggest this feature will be called "Signal Login" and will indeed be a paid feature.

Since payment info can be just as identifying as a phone number, its unclear how Signal plans to protect the privacy of users' payment info.