Unify the two branches in the consistency proof check - #149
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Also replace prepending to the proof list with removing in the other branch. It makes it a little obvious how to implement this without making a copy of the proof. This should also hopefully make the relationship between inclusion and consistency proof evaluation clearer. While I'm here, use '1.' for the steps so we don't have to renumber it as it changes.
lukevalenta
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Nice refactor! Just a couple comments.
| 4. Right-shift `sn` once more. | ||
| 5. Compare `sn` to `0` and `r` to `root_hash`. If either is not equal, fail the proof verification. If all are equal, accept the proof. | ||
| 2. Otherwise, run the following: | ||
| 1. Set `fn` to `start`, `sn` to `end - 1`, and `tn` to `n - 1`. |
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As I'm re-implementing this logic, I found a panic in the original version of my code when n = 0 due to an underflow. The fact that [start, end) is a subtree of the tree of size n implies that 0 <= start < end <= n so it must be the case that end > 0 and n > 0, but maybe we should add an explicit note about that?
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Hmm... how about we just make the function check the preconditions? It's fallible anyway, and makes it consistent with the inclusion proof version. Arguably it's redundant with the "type signature" but people will be sloppy.
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See ietf-plants-wg/merkle-tree-certs#149 for details. As an added bonus, this removes a `clone()` of the proof.
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See ietf-plants-wg/merkle-tree-certs#149 for details. As an added bonus, this removes a `clone()` of the proof.
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See ietf-plants-wg/merkle-tree-certs#149 for details. As an added bonus, this removes a `clone()` of the proof.
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Also replace prepending to the proof list with removing in the other branch. It makes it a little obvious how to implement this without making a copy of the proof. This should also hopefully make the relationship between inclusion and consistency proof evaluation clearer.
While I'm here, use '1.' for the steps so we don't have to renumber it as it changes.
(CC @nharper)