14 Aug '12, 11am
Pendant que #Bitcoin se développe, les chercheurs avancent sur la monnaie quantique, fondamentalement anonyme #science
The no-cloning theorem means we should not think of qubits the same way we think about bits. One might imagine using a handful of qubits as a form of money. A mint could produce some qubits using some process known only to it, and anyone else, given just those qubits, could not copy them by any means without further information. The no-cloning theorem does not immediately imply secure quantum money is possible; it only says that machines that can copy all quantum states are impossible, and a counterfeiter would be content with a machine that only copied quantum states that represented valid quantum money. A counterfeiter could also try to obtain additional information about the quantum money state by using the algorithm that a merchant would use to verify quantum money. By examining concrete schemes for quantum money, we will see how these kinds of attacks can be avoided.