Post-Quantum Anchor

A post-quantum anchor ties a certificate of post-quantum signatures into the data that a block hash covers. The problem it addresses is retroactive. Classical signatures stay verifiable in the record forever, so an attacker who later recovered old validator keys could, in principle, re-sign an alternative history that looks as valid as the real one. An anchor leaves periodic evidence in the chain that was signed with a scheme designed to resist that recovery, and it binds that evidence under the block hash so it cannot be detached or replaced afterwards.

On chain 2800 the anchor has been live since block 13,014,000. Every 32nd block header carries a seal certificate of Falcon-512 signatures from the validators over the parent block, and a 32-byte digest of that certificate sits inside the data covered by the block hash. The rule enforced today requires at least 3 signatures per anchor block; in practice certificates carry 5, the configured cap. The signers are the 9 entries of the signer registry, bound on-chain in an immutable contract whose storage holds the registry keccak.

Two boundaries matter. Block production and finality on chain 2800 still run on classical ECDSA secp256k1 signatures under QBFT; the anchor adds post-quantum evidence to the record, it does not make consensus post-quantum. The Falcon-512 verification the anchor relies on is itself available on-chain: five post-quantum precompiles have been live since block 9,189,161 at addresses 0x0AE1 to 0x0AE5, validated against NIST test vectors.