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Phishing-Resistant Phone Number Attestation for MFA
draft-brown-spice-phishing-resist-attestation-00

Document Type Expired Internet-Draft (individual)
Expired & archived
Author Derek Brown
Last updated 2026-05-07 (Latest revision 2025-11-03)
RFC stream (None)
Intended RFC status (None)
Formats
Stream Stream state (No stream defined)
Consensus boilerplate Unknown
RFC Editor Note (None)
IESG IESG state Expired
Telechat date (None)
Responsible AD (None)
Send notices to (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft is available in these formats:

Abstract

This draft introduces a phishing-resistant phone number attestation mechanism for multi-factor authentication (MFA). Conceptually similar to WebAuthn, it uses origin-bound cryptographic challenges to ensure that users only attest ownership of their phone numbers to legitimate relying parties. The protocol leverages network-operator- issued verifiable credentials (VCs) that cryptographically bind phone number ownership to a user's device. Applications present origin- scoped challenges that users sign using their VC, ensuring secure, domain-specific authentication and mitigating replay, relay, and phishing attacks- without relying on SMS-based one-time passwords (OTPs).

Authors

Derek Brown

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)