A blockchain that signs every transaction with FIPS 204 ML-DSA-87 keeps 4,627 bytes of signature per transaction forever. We describe and measure an archive certificate: one hash-based proof, for a range of already validated blocks, of knowledge of canonical FIPS 204 signatures on exactly the recorded messages under the keys resolved from chain state. Fresh blocks keep native verification. The construction starts from an exact bounded relation for ML-DSA-87 verification once the high bits $u = w'_1$ are fixed. The main certificate keeps $u$ hidden and proves the SHAKE256 challenge hash inside the proof, by a GKR argument for Keccak-f[1600] over the same WHIR commitment as the lattice relation.
For 65,536 signatures we measured 104.09 bytes per signature in a Johnson-regime family, which has a classical bound only, and 126.89 in a unique-decoding family, against 4,627 bytes raw. The price is a slow prover and a verifier slower than native verification. At $2^{64}$ queries and $2^{20}$ verification submissions, under the compiler, coding and extractor-efficiency hypotheses specified in the security analysis, the classical random-oracle extraction error is below $2^{-188.07}$ for the Johnson family and below $2^{-201.99}$ for unique decoding. In the quantum random oracle model we state, for the unique-decoding family only, an extraction-failure bound below $2^{-129.67}$ at $2^{64}$ quantum queries and $2^{20}$ verification submissions; it is not a work factor.
Lean 4 checks Lemmas 1 to 4 and the WHIR steps at the scopes detailed in the formal-verification section, the registered interactive theorem's conditions K1–K4, exact ledger arithmetic, and conditional compiler compositions. The extractor's efficiency condition K5 is derived in a defined bit-cost model from two implementation premises that remain open. The link between the interactive predicate and the ledger is proved within an abstract compiler interface; concrete compiled security games and correspondence with the Rust verifier remain outside the checked result. The bundles identified in that section are also verified with AXLE. An external review is outstanding, and certificate-only bootstrap remains disabled under the stated deployment conditions.