Business game “Digital cash”

The article describes a cryptographical protocol that implements “electronic cash”, that is, a payment system in which the role of “cash” is played by a pair of numbers, signed anonymously on the secret key of the issuing bank. The protocol is implemented in the RSA cryptosystem using relatively small numbers, which, however, is sufficient to illustrate the main ideas of the protocol. To increase the interest in this topic, the protocol is presented in the form of the business game Digital cash, which is a model of the financial and economic electronic payment system (EPS). The business game is intended for use in the educational process and is a multi-level task for generating and verifying the authenticity of “electronic cash”. The student must know a fluent command of the possibilities of modern programming and the knowledge of information flows in EPS.