library
A curated reference atlas of the standards, protocols, and topics I work on — annotated, cross-linked, maintained over time.
The factual half of appliedbits — descriptions of how things work and what the standards say, with references to the authoritative documents. The opinionated half lives in the notebook. It's organized around nine anchor topics, each with its own index, and it includes a small set of interactive tools.
Free, client-side utilities for the trust & identity beat — decode PASSporTs and STIR/SHAKEN certificates, and look up US carriers.
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Caller authentication and the trust framework
The cryptographic call-authentication framework deployed across North American telephone networks. STIR is the IETF protocol layer; SHAKEN is the operational profile and governance arrangement that ATIS specified for North American carriers. This page is the overview and history; deeper topics get their own pages.
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Domain-bound caller identity and the next-generation trust framework
VESPER extends the STIR architecture by defining a delegate-certificate profile that binds three things in a single auditable trust artifact — telephone-number authority (via TNAuthList), the responsible entity's domain (via SubjectAltName), and a Signed Certificate Timestamp from a public transparency log. The certificate itself is the trust artifact; standard PASSporTs (RFC 8225) signed by it carry the assertions on the wire. A separate RTU Token form provides portable proof outside SIP. The framework is active at the IETF as a set of related drafts I'm authoring; it has been the primary motivation for the STIR working group's expanded rechartering scope.
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Within-jurisdiction policies, enforcement, and cross-border trust frameworks
How telephone-number trust frameworks are governed — the participation rules and enforcement mechanisms within each country, and the architectures that coordinate trust across jurisdictions. Bridges STIR/SHAKEN as a technical framework into the larger questions of policy, accountability, and international harmonization.
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RFCs and active drafts referenced across the library
A catalog of IETF documents referenced across the library. Published RFCs and active working-group drafts each get their own page; topical pages elsewhere on the site link here as the canonical reference home.
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Cross-topic terminology reference
A cross-topic reference for the acronyms and short-form terms that recur across the library — primarily STIR/SHAKEN, number administration, and US telecommunications governance vocabulary. Each entry is a one-or-two-sentence definition; for terms that have their own library page, the entry is a stub that hands off to that page. Alphabetical order is the only structure.