Vitalik: Signal is exploring registration without a phone number, true privacy still requires that messages cannot be linked

Ethereum co-founder Vitalik Buterin stated that Signal recently announced it is exploring allowing users to register accounts without a phone number. He welcomed this move, believing it helps reduce reliance on the highly oligopolistic system of phone numbers, lowers the identity security risks associated with SIM card swaps, and makes it more difficult for governments to pressure Signal to ban users based on nationality.

Vitalik also pointed out that while this initiative is better for privacy protection than the current situation, it only achieves "confidentiality" and does not reach true anonymity, as metadata such as message sending time, frequency, and recipients could still be used for identity correlation. He believes that with the development of artificial intelligence technology, long-lasting anonymous accounts are becoming outdated, and the only defensible form of privacy is "message-by-message uncorrelatable," meaning that no one other than the sender and receiver knows the identities of the communicating parties. This direction is currently being explored and advanced by new communication tools and mixing network projects such as Session and SimpleX. Additionally, protection against spam and denial-of-service attacks will become the next key issues to address.