We show that the single-server computational PIR protocol proposed by Holzbaur, Hol- lanti and Wachter-Zeh in [HHW20] is not private, in the sense that the server can recover in polynomial time the index of the desired file with very high probability. The attack relies on the following observation. Removing rows…
We analyze from the game theory point of view Byzantine Fault Tolerant blockchains when processes exhibit rational or Byzantine behavior. Our work is the first to model the Byzantine- consensus based blockchains as a committee coordination game. Our first contribution is to offer a game-theoretical methodology to analyse equilibrium interactions…
The introduction of a central bank digital currency (CBDC) allows the central bank to engage in large-scale intermediation by competing with private financial intermediaries for deposits. Yet, since a central bank is not an investment expert, it cannot invest in long-term projects itself, but relies on investment banks to do…
In a novel model of an endowment economy, we analyze coexistence and competition between traditional fiat money (Dollar) and another intrinsically worthless medium of exchange, not controlled by a central bank, such as Bitcoin. Agents can trade consumption goods in either currency or hold on to currency for speculative purposes….
We analyze a two-country economy with complete markets, featuring two national currencies as well as a global (crypto)currency. If the global currency is used in both countries, the national nominal interest rates must be equal and the exchange rate between the national currencies is a risk-adjusted martingale. We call the…
