Jan van Eyck. The Arnolfini Portrait, 1434 (detail of the mirror)
In Jan van Eyck's Arnolfini Portrait, art becomes a "visual document" certifying the marriage, a proof of authenticity through light, detail and the play of mirrors. The painting is a "seal" bearing witness to the event, fixing it in a visible, immutable act.
Like the blockchain, which guarantees the origin of works, the painting acts as a "digital certificate" binding image and reality. The reflection in the mirror, showing the painter and a possible witness, suggests transparency and truth, concepts central to the certification of authenticity.