§1. In the diocesan curia there is also to be a secret archive, or at least in the common archive there is to be a safe or cabinet, completely closed and locked, which cannot be removed; in it documents to be kept secret are to be protected most securely.
§2. Each year documents of criminal cases in matters of morals, in which the accused parties have died or ten years have elapsed from the condemnatory sentence, are to be destroyed. A brief summary of what occurred along with the text of the definitive sentence is to be retained.
Source: Code of Canon Law (Vatican.va)