Method for encrypted data exchange and communication system

摘要

The method involves calculating a result of a scalar multiplication by the latter subscriber on a query of the former subscriber. A function value is determined from the result of the scalar multiplication with the help of non-injective reference, so that the function value does not allow clear conclusion on the result. The function value is transmitted back to the former subscriber as a response. The response comprises an x-coordinate of a point on the elliptical curve. An independent claim is included for a communication system for authentication of the subscribers of the communication system using cryptography with a data communicative connection.