CryptoHead

Very welcome recent news from Signal: they are working on letting you register an account without a phone number. aboutsignal.com/news/signal-… That said, an important counterpoint about what this would and would not accomplish. The good #1: reducing dependence on phone numbers. Even aside from privacy benefits, reducing dependency on a highly oligopolistic system of chokepoints is good in itself. The good #2: phone numbers are for many people not a good "root" of identity from an access control perspective. Phone numbers get sim swapped all the time. The good #3: allowing phone-number-free accounts will make it harder for them in the future to discriminate against people by country - and so make it harder for governments to pressure them to block their own citizens. Now, on privacy. Significantly better than status quo, so yes it is good #4, but... In practice, in 2026, I believe that pseudonymity (a long-term persistent account that is not tied to your primary identity) is a dead concept. There are just too many channels by which we accidentally slowly leak data about who we are - timing of messages, the pattern of who we send messages to with what frequency, size, etc. And too many highly effective AI-based means (both using LLMs per-user, and LLMs helping every person and agency under the sun use math that we had all along) to uncover and piece together those hints. As a trivial example, whatever server you interact with learns your IP address, but even if you hide *that* with a VPN or Tor, there are many other identity leakage vectors. And so the only defensible form of privacy is *message-by-message unlinkability* - no one except sender and receiver knows the (sender, receiver) pair, ideally even not knowing who the sender or the receiver are. A natural taxonomy of privacy is the following 2x2: * Sitting duck: adversary knows "X did Y" * Confidentiality: adversary knows "X did ???" [E2E encryption provides this] * Anonymity: adversary knows "??? did Y" [aka message-by-message unlinkability] * Ideal: adversary knows "??? did ???" Signal has already had confidentiality for a long time. (Note: in other contexts, "confidentiality" sometimes means "someone knows X did Y, and we trust that someone to not reveal it", ie. not true privacy. Here, by confidentiality we mean hiding contents from third parties) This adds pseudonymity: in the above schema, adversary knows "0x8b512c... did Y", where they don't initially know who 0x8b512c... is, but may figure that out over time. The ideal is getting to message-by-message unlinkability. Actually accomplishing that gets into territory that is currently being explored by mixnet projects as well as newer messengers, eg. @session_app and @SimpleXChat. Once we get deeper into this territory, I suspect the primary frontier will be spam and DoS protection. Right now, much of the internet blocks all Tor exit nodes - not because they personally hate privacy, but because that's where DoS attacks come from. So we need ways for people to prove their non-spammer status while maintaining message-by-message unlinkability. See here github.com/dmarzzz/reputatio… for one direction (which complements ethresear.ch/t/zk-api-usage-… nicely). So I hope that we appreciate the victory that is mainstreaming of end-to-end encryption, that we actually get Signal accounts without phone number dependency (it's a great thing even if it had zero privacy consequences), and then that we keep moving forward and pushing the frontier of data leakage minimization.