You must provide a real phone number to use Signal, and Signal or its partners will send you verification texts or calls to that number when you sign up.
Your phone number — a persistent real-world identifier — is required to use Signal and is shared with third-party SMS verification providers, meaning Signal's privacy protections do not fully extend to account registration anonymity.
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Compare across platforms →Despite Signal's strong privacy architecture, the mandatory phone number requirement creates a persistent identifier linkable to real-world identity, which is shared with third-party verification providers and partially undermines anonymity.
(1) REGULATORY FRAMEWORK: Collection of phone numbers triggers GDPR Art. 4(1) personal data definitions and Art. 6 lawful basis requirements (no explicit basis stated). CCPA §1798.140 defines phone numbers as personal information subject to disclosure and deletion rights. TCPA (47 U.S.C. §227) governs consent to receive SMS verification messages — the policy's consent mechanism appears adequate. COPPA (16 CFR §312) requires parental consent for users under 13; the policy sets a minimum age of 13 but provides no mechanism for age verification. (2)
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