The review has examined the mechanisms that come nearest to the problem one at a time. This entry and the one that follows widen the lens to the two fields those mechanisms belong to, because a claim about a gap is stronger when it is set against a surveyed landscape rather than a handful of isolated specifications. The first field is software supply-chain security, the mature discipline for establishing that an artefact can be trusted not because it looks right but because its origin and integrity have been attested.
A field organized around three properties
Software supply-chain security has, in recent years, been systematized into a small and clarifying set of properties. A recent systematization of knowledge organizes the whole field around three (Okafor et al., 2024). Transparency is knowing what is in the chain, provided by bills of materials and by transparency logs that record signing events in an auditable ledger. Validity is the chain remaining correct, in the specific sense that components are unchanged by unauthorized parties and the actors who change them are authenticated. Separation is compartmentalizing the chain so that a compromise in one place cannot propagate to another. Against these three the field sets a four-stage picture of how supply-chain attacks unfold, from an initial compromise, through alteration and propagation, to eventual exploitation downstream, with the SolarWinds intrusion as the worked example.
This framing is useful here because it lets the field be judged on its own terms rather than through the narrow lens of a single tool. And judged on its own terms, it draws the line this work depends on.
What integrity establishes, and what it leaves open
The validity property is the one that matters, and it is worth being exact about what it does. It establishes that an artefact is the unchanged output of an authorized process. It does not establish that the artefact is correct, or safe, or fit for the use its recipient intends. Those are different questions, and the systematization is candid about the difference: it notes that heavy reliance on external components has decreased the confidence that systems only do what they are intended to do (Okafor et al., 2024). Signing and attestation restore confidence in provenance and integrity. The question of whether the thing then does what it should is left open.
That open question is admissibility, named in the supply-chain field's own words. The point is not a criticism of these mechanisms, which do their own job well. It is that their job is a different one. An attestation framework confirms that tampering has not occurred between the steps of a chain. It does not, and does not claim to, confirm that the output of a step is correct or that the artefact is fit to act on. Integrity is established; fitness is not. A perfectly attested component can still be the wrong thing to install, just as a perfectly signed claim can still be one that should not be acted upon. The supply-chain field has built an impressive apparatus for the first half of that sentence and has, by its own admission, left the second half open.
A principle worth carrying forward
One of the three properties deserves a note, because it recurs later in an unexpected place. Separation, the compartmentalizing of a chain so that compromise cannot propagate, is the same instinct that network security expresses as the demilitarized zone and that operational technology, examined next, expresses as zones and conduits. The supply-chain field arrives at it independently: trust should be attached and contained deliberately, never allowed to spread by proximity or assumption. That three separate disciplines reach the same conclusion is a thread this review picks up again, because it points at something the discipline this work proposes is built to honour.
References
Okafor, C., Schorlemmer, T. R., Torres-Arias, S. and Davis, J. C. (2024). SoK: Analysis of Software Supply Chain Security by Establishing Secure Design Properties. arXiv preprint arXiv:2406.10109. arxiv.org/abs/2406.10109