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SLSA: Supply-chain Levels for Software Artifacts (What to actually implement)

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SLSA is a maturity model for build provenance and tamper resistance. The real value is disciplined build pipelines and signed attestations.

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supply-chainbuildprovenanceslsa
Trust and provenance

Editorial record

Sources

  • slsa.devSLSA specification v1.2

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    SLSA specification v1.2
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TL;DR

  • SLSA uses tracks and levels to describe increasing supply-chain security guarantees.
  • The core primitive is provenance: “this artifact came from this source, built by this workflow, with these dependencies.”
  • Start with repeatable builds + CI hardening + signed attestations; don’t jump straight to maximalism.

What it is

SLSA (pronounced “salsa”) is a framework/maturity model that defines requirements for:

  • source integrity
  • build integrity
  • provenance generation and verification

Key ideas

  • Provenance beats vibes: you want machine-verifiable metadata.
  • Build systems are attack surfaces: lock down runners, permissions, and dependencies.
  • Verification is the endgame: storing provenance is not enough—you need policies that reject untrusted artifacts.

Recommended actions

  • Now:
    • Move builds to CI (not laptops).
    • Enable branch protections + required reviews for release branches.
  • Soon:
    • Produce signed provenance/attestations for releases.
    • Pin dependencies and lockfiles; monitor for tampering.
  • Later:
    • Enforce verification gates in deployment (reject artifacts without valid provenance).

Notes / caveats

  • SLSA doesn’t magically fix supply-chain risk; it gives you a way to measure and enforce build trust.

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