nx_ltv_lib.nx

nx_ltv_lib.nx -- PAdES LONG-TERM VALIDATION (ETSI EN 319 142 baseline levels B-B/B-T/B-LT/B-LTA). The gap this closes: a signature that verifies TODAY is worthless if it cannot be verified in the year the dispute actually reaches a court. Signing certificates expire in 1-3 years; litigation and record retention run 7-30. Once the certificate expires -- or the issuing CA's OCSP responder goes dark, or the CA dissolves -- a verifier can no longer fetch the revocation status the signature depends on. THE LEVELS, each strictly containing the last: B-B signed attributes + the signer certificate (verifiable only while the cert lives) B-T + a trusted timestamp token (proves WHEN it was signed) B-LT + the certificate chain AND revocation data EMBEDDED (carries its own proof; no live CA) B-LTA + an archive timestamp over the whole structure (survives crypto obsolescence) THE TOOTH EVERY NAIVE VERIFIER GETS WRONG: when a signature can no longer be checked the answer is INDETERMINATE, *not* INVALID. Those are opposite legal outcomes -- INVALID says forged or tampered; INDETERMINATE says our evidence decayed. Reporting an expired-cert B-level signature as "invalid" impeaches a document that was perfectly validly signed. The verdict is THREE-valued so the distinction cannot be collapsed into a boolean, which is exactly how it gets lost. THE SECOND TOOTH: long-term validation is NOT a laundry. A certificate already REVOKED at signing time stays INVALID at B-LTA -- embedding proof of a bad status proves the status was bad. STRUCTURE (two layers, deliberately): a PURE DECISION CORE holding the level and verdict rules as total functions, and REGISTRY ADAPTERS that fetch components and delegate. The rules therefore gate with ZERO writes and cannot be held hostage by a storage stall (debt 1785519597), and there is exactly one copy of each rule so the two layers can never disagree. SCALE ENVELOPE (declared): pure core O(1), allocation-free; adapters one reg_get per component. DRY: composes nx_matter_lib. license_tier: ORIGINAL LIB.