TolP
Trust Spanning-layer Protocol (TSP)
Proposal A Secure Identifier Overlay for the Internet
Samuel M. Smith Ph.D. sam@keri.one https://keri.one 2023/02/08
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Aweaker spanning layer (less functionality) has fewer supported applications but more possible supports than a stronger spanning layer ‘Weaker means less functionality. Astronger spanning layer (more functionality) has fewer possible supports but more supported applications Aminimally sufficient spanning layer is the weakest possible layer that still supports the necessary applications —of [ NINecessary Applcations ———————————£> | <I<—Fewer Applications. S ~ / // /- —> ‘Spanning Layer S <t Weaker (fower applications) N\ T ~ << < Al Possiblo Supparts > £ More Supports tpsacm ac.orgimagazinesfioraif771g nhe hourgass madelfultext
Features of a Spanning Layer simplicity: Only one way to access (orthogonality) any service or resource through the spanning layer Generality: The spanning layer has the richest set of possible applications without increasing its logical strength Resource Limiting: The spanning layer abstracts and limits resource access by supported applications Deployment Scalability: widespread adoption though minimally essential functionality
Application 1 Application 2 Application 3 Spanning Layer S / T~ e Support 1 Support 2 Support 3
Implications of the Hourglass Theorem Deployment scalability is enabled by a spanning layer that has implementations using as many different supports as possible Broader adoption comes from increasing the support Aminimally sufficient spanning layer may not be defensibly monetizable because monetization disincentivizes broader aupport —> | <———————— Al Necessary Applications —————————————> | <I<—— Fewer Applications ‘\\ _— - ~ /) ~ - — Spanning Layer S <jep— Weaker (fewer applications) - N Q T < 5 Moo Spgts ] ot oSaprs
Adoption of a common service interface is a key to interoperability, portability, and “future proofing” in the face of rapid technological change.
The design of both the internet and Unix followed the hourglass principle leading to dominance while stil allowing disruptive innovation.
Successful interface design adheres to the discipline of simplicity, generality, and resource limitation of the common interface
The deployment scalability trade-off is that broader adoption comes from thinning or weakening the spanning layer KERI design guidance from hourglass principle: address only = namespace agnostic, portable, primary root-of-trust is portable verifiable data structure, secondary roots-of-trust are replaceable
Hourglass Theorem Summary T —— & | < Al Necessary Applcaions ———————————> | <I<—_Fewer Applcations . i Weaker (lewer appications)
<< [ —————————— AllPossible Supporls ———————————1> | —>> More Supporls Minimally sufficient spanning layer singularly spans supporting protocols below it and applying protocols above it. The degree of dominance of a spanning layer is eco-system validation of the preferred design
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