A method for authentication and identification uses different keys for the
prover and the verifier, but on the other hand dispenses with the
utilization of long number modulo arithmetic by the use of simple basic
components such as, for example, arithmetic operations in finite bodies
GF(2.sup.n). A private key is stored in the prover, so that the latter
can receive, in encrypted form, data elements generated as random
elements and can itself utilize them again as key for an authentication
method of a data set to be transmitted. The verifier receives the
authenticator thus formed and checks it. If the data set is generated by
the verifier and transmitted to the prover, then this method can serve
for the identification of the prover. The method is particularly
advantageous in the area of smart cards, since there the required space
in the hardware implementation can be considerably reduced.