Authenticity

Each artwork is its specification: a small canonical description that a deterministic renderer turns into the identical image at any size, forever. Its identity is the SHA-256 fingerprint of that specification. At purchase, a canonical certificate string — fingerprint, seed, date, buyer, product — is signed with ML-DSA-65, the NIST FIPS 204 post-quantum signature, under the Mood Art key, whose public half is published on this site.

Any browser can verify a certificate offline at /verify: recompute the fingerprint from the specification, check the signature against the public key. No trust in this server is required, and any altered field breaks the proof.

Ownership

At claiming, the buyer's own browser generates a personal ML-DSA keypair; the private key exists only in their downloaded key file. The site signs a binding between artwork and owner key and records the public key in a registry. Ownership is then proven by challenge–response at /prove: a doubter sends a fresh random nonce, the owner returns a signature over it, and it is verified against the registered key.

The certificate can be shown publicly — it proves nothing without the answering key — and every proof is bound to its one-time nonce, so intercepted proofs are worthless.

Transfer

The Mood Art signature is the painter's mark and never changes; what moves is the ownership binding. The current owner signs an endorsement naming the new owner's key; the registry accepts it only from the currently registered owner and appends it to the chain. The full provenance history stays verifiable offline — and double-selling is impossible, because a past owner can no longer endorse.

Quantum safety

A quantum computer threatens cryptography through Shor's algorithm, which breaks RSA and elliptic curves — neither of which appears anywhere here. The hashes face only Grover's quadratic speedup, keeping ~128-bit security; and every signature — certificates, ownership proofs, transfer endorsements — is ML-DSA-65, built on lattice problems (standardized from CRYSTALS-Dilithium) with no known quantum shortcut.

Nothing in the chain is quantum-breakable: no forged certificates, no impersonated owners, no fabricated transfers — today, or after the quantum era arrives.