Off-line e-cash systems are the digital analogue of regular cash. One of the main desirable properties is anonymity: spending a coin should not reveal the identity of the spender and, at the same time, users should not be able to double-spend coins without being detected. Compact e-cash systems make it possible to store a wallet of O(2 L ) coins using O(L + λ) bits, where λ is the security parameter. They are called divisible whenever the user has the flexibility of spending an amount of 2 , for some ≤ L, more efficiently than by repeatedly spending individual coins. This paper presents the first construction of divisible e-cash in the standard model (i.e., without the random oracle heuristic). The scheme allows a user to obtain a wallet of 2 L coins by running a withdrawal protocol with the bank. Our construction is built on the traditional binary tree approach, where the wallet is organized in such a way that the monetary value of a coin depends on how deep the coin is in the tree.
In 2012, Izabachène and Libert REF constructed the first PDEC in the Standard Model based on a binary tree,where the monetary value of a coin depends on how deep the coin is in the tree.
Divisible e-cash in the standard model
Pairing
Computer Science