A key a quantum computer can't break. Made here, in milliseconds.

One square per byte.

The account checks this signature on chain before it acts.

Every wallet key on Ethereum-style chains is an ECDSA key on the secp256k1 curve. Its safety rests on the discrete-log problem. Shor's algorithm, run on a large fault-tolerant quantum computer, solves that problem efficiently: give it a public key and it returns the private key.

Your address is only a hash of the public key. The key itself goes public the first time the wallet signs a transaction, and from then on it is on chain for good.

Shor's algorithm needs the hidden structure of factoring and discrete logs. Hash-based signatures rest only on a hash function, where the best known quantum attack (Grover's search) gives a square-root speed-up that longer outputs absorb. Lattice-based schemes such as Falcon rest on finding short vectors in high-dimensional lattices, for which no efficient quantum algorithm is known.

Falcon-512 is NIST's FN-DSA: small for a post-quantum scheme, and fast to verify, which is what an on-chain check needs.

Anything that loosens control waits in a public timelock where this key can veto it, and freeze, recover and withdraw-all need only this key, so control of the account rests on Falcon. The agent's session key is ordinary ECDSA: it expires, and even a broken one can only trade inside the mandate until this key freezes the account.