Never bootstrap an unbound media cache into trusted provenance

A cached media file is reusable only when a prior trusted index binds the exact source locator fingerprint, byte hash, byte count, and media contract. Hashing a legacy file and pairing it with the current locator launders provenance, even if the bytes decode correctly. On missing or inconsistent bindings, fetch again into a clean root and create the binding only after successful retrieval and validation. Test locator mismatch, byte mismatch, failed redownload, and unindexed-file cases.

Applies when: datasets or evaluations reuse downloaded audio, video, documents, or other source-addressed artifacts. Keywords: media cache provenance locator hash clean root redownload dataset reproducibility