[CT-90] No test for a cache-key collision between SHA-256 and SHA-512 anchors of related content

[mftee]

Overview

SC-07 added SHA-512 anchoring alongside the original SHA-256 support, but contract/src/cache.rs's cache-key construction should be confirmed to namespace by hash algorithm — otherwise a SHA-256 hash and an unrelated SHA-512 hash that happen to share a prefix/value space could collide in the cache and return the wrong verification result.

Tasks

• Confirm (or add) the hash algorithm as part of the cache key, not just the hash value
• Add a test asserting a SHA-256 and a SHA-512 entry with a contrived overlapping key component don't collide

Acceptance Criteria

• Cache keys are namespaced by hash algorithm, verified by a dedicated test

Notes for Contributors

Comment below to be assigned.

[Prz-droid]

GM Maintainer, I’d like to take on this issue. I’ll inspect the cache-key construction to confirm that the hash algorithm is included in the namespace and, if necessary, update it so SHA-256 and SHA-512 entries can never collide. I’ll add a focused regression test using contrived overlapping key components to prove the algorithms remain isolated, then run the relevant test suite and keep the change minimal and easy to review.
ETA: 48 hours