A device for the computer-aided creation of an asymmetric checksum by a first communication partner, in which a processor calculates a mapped checksum by means of bijective mapping from a first checksum, wherein the first checksum from the set of all possible checksums is assigned by means of a first function to respectively one message from a set of all possible messages, the first checksum is prepared in particular by mapping the set of all possible checksums onto a first set by a second function. Information is distributed which defines an inverse function relative to the bijective mapping to at least one second communication partner, wherein the first checksum is calculated from the mapped checksum by means of the inverse function. The mapped checksum and the message are transmitted to the at least one second communication partner.