Quantum Money from Class Group Actions on Elliptic Curves
摘要
We construct a quantum money/quantum lightning scheme from class group actions on elliptic curves over \(\mathbb {F}_p\) . Our scheme, which is based on the invariant money construction of Liu-Montgomery-Zhandry (Eurocrypt’23), is simple to describe. We believe it to be the most instantiable and well-defined quantum money construction known so far. The security of our quantum lightning construction is exactly equivalent to the (conjectured) hardness of constructing two uniform superpositions over elliptic curves in an isogeny class which is acted on simply transitively by an exponentially large ideal class group. However, we needed to advance the state of the art of isogenies in order to achieve our scheme. In particular, we show: Achieving these results also requires us to advance the state of the art of the (pure) mathematics of elliptic curves, and we are optimistic that the mathematical tools we developed in this paper can be used to advance isogeny-based cryptography in other ways.