Clarify verification process - #144
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Matt Mueller noticed that the process was ambiguous about where the MTCProof fields came from, and that we didn't consistently rename the OID to match the id-alg-* convention that LAMPS seems to be using these days. From there I also noticed that the shape of RFC 9162, section 2.1.3.2 doesn't quite fit what we need. We want to run the inclusion proof, get the expected subtree hash, and then check a signature over it. RFC 9162 assumes you already know the subtree hash and are just checking it. I copy-pasted the description from RFC 9162 and inlined the small changes we were making.
The index check as already in there per RFC 9162. Putting both there is tidy.
davidben
commented
Sep 16, 2025
| 1. Check that the TBSCertificate's `signature` field is `id-mtc-proof` with omitted parameters. If either check fails, abort this process and fail verification. | ||
| 1. Check that the TBSCertificate's `signature` field is `id-alg-mtcProof` with omitted parameters. If either check fails, abort this process and fail verification. | ||
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| 1. Let `index` be the certificate's serial number. Check that `start <= index < end`, and that `[start, end)` describes a subtree per {{definition-of-a-subtree}}. If either check fails, abort this process and fail verification. |
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This is implicit in subtree evaluation now.
bwesterb
approved these changes
Sep 17, 2025
lukevalenta
reviewed
Sep 17, 2025
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Matt Mueller noticed that the process was ambiguous about where the MTCProof fields came from, and that we didn't consistently rename the OID to match the id-alg-* convention that LAMPS seems to be using these days.
From there I also noticed that the shape of RFC 9162, section 2.1.3.2 doesn't quite fit what we need. We want to run the inclusion proof, get the expected subtree hash, and then check a signature over it. RFC 9162 assumes you already know the subtree hash and are just checking it. I copy-pasted the description from RFC 9162 and inlined the small changes we were making.