Changes to BIP-360 - Pay to Quantum Resistant Hash (P2QRH)

The recent proposal regarding spend-path vectors has been formally submitted as a pull request on GitHub, specifically filed under bitcoin/bips2232. This addition follows the structure outlined by BIP 341, particularly using 'wallet-test-vectors.json'. The submission includes a detailed schema featuring one six-input transaction designed to validate various cases. This includes a depth-128 control block that adheres to the maximum size limit of 4097 bytes. Additionally, the proposal encompasses nine transactions aimed at testing invalid scenarios. These are particularly focused on assessing the rules associated with control block size and depth limits.

Importantly, the keys and previous outputs (prevouts) utilized in these tests are derived from fixed sha256 tags, ensuring consistency and reliability in testing. It is worth noting that some of the trees employed in these tests have been previously used and can be found in 'p2mr_construction.json', allowing for cross-verification between the two files to enhance accuracy and coherence.

A specific issue was identified during the documentation of these vectors concerning the control byte's low bit, which is described in the specification as "unused and must be 1". The current validation steps, however, do not explicitly include a failure condition if this requirement is not met, unlike other rules in the section. This discrepancy suggests a potential oversight in enforcement, implying that if non-enforcement was intended, relevant documentation should be adjusted to reflect this, possibly by omitting this case or revising the accompanying footnote for clarity. This point has been clearly articulated within the pull request to ensure it is addressed appropriately.