> For the complete documentation index, see [llms.txt](https://sector0.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sector0.gitbook.io/docs/architecture-and-security/architecture.md).

# Architecture Overview

Core architecture, mathematical non-repudiation, threat modeling, and cryptographic specifications.

Deep technical documentation detailing the internal design, security architecture, cryptographic contracts, and empirical performance metrics of s0.

***

## Architectural Core

<table data-view="cards"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><strong>System Architecture</strong></td><td>Three-tier architecture blueprint: UI presentation layer, core operational modules, and zero-trust cryptographic core.</td><td><a href="/docs/architecture-and-security/system-architecture.md">System Architecture</a></td></tr><tr><td><strong>Security Model &#x26; Threat Matrix</strong></td><td>Formal adversary capabilities, mitigations, key lifecycles, and physical hardware boundaries (FTL, CoW, journaling).</td><td><a href="/docs/architecture-and-security/security-model.md">Security Model</a></td></tr><tr><td><strong>Certificate Schema &#x26; Canonical JSON</strong></td><td>s0-cert-v1.0.0 JSON schema, pure Ed25519 digital signatures, and the 7 deterministic serialization rules of Canonical JSON v1.</td><td><a href="/docs/architecture-and-security/certificate-spec.md">Certificate &amp; Canonical JSON Spec</a></td></tr><tr><td><strong>Verification &#x26; Air-Gapped Trust</strong></td><td>Air-gapped verification architecture, 100% in-browser WebCrypto execution, and optical QR trust workflows.</td><td><a href="/docs/architecture-and-security/verification.md">Verification &amp; Air-Gapped Trust</a></td></tr><tr><td><strong>Performance Benchmarks</strong></td><td>Empirical I/O bus throughput benchmarks, NVMe bus saturation, and constant-memory (38-65 MiB RSS) streaming metrics.</td><td><a href="/docs/architecture-and-security/performance.md">Performance Benchmarks</a></td></tr></tbody></table>


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