A Quantum-Resistant Implementation of a Digital Cash System with Valued and no-Valued e-Coins

Digital cash is a form of money that is minted, stored, and spent digitally. As opposed to debit or credit cards, it enables untraceable payments in the sense that the payer can acquire products while keeping their identity secret. In a recent paper, a new digital cash paradigm including the so-called no-valued e-coins was proposed. No-valued e-coins are used to perform bogus transactions which mask consumption patterns. In this paper, we analyze the aforementioned cash paradigm and investigate the possibility of implementing it over quantumresistant cryptographic schemes. This objective has been achieved using off-the-shelf cryptosystems for data encryption and digital signature which have been deeply analyzed to check they provide the required features.