To reduce memories required for authentication processing and to avoid repeating of processing by constituting a second processing means so as to confirm authentication information by verifying an equation having a coefficient, a number of public powers, a maker, a random exponent, a shaded identifier and a title as variables.
A first transmission means transmits an identifier I and a title T to a verification station. The second processing means of the verification station fetches a random exponent D within a range from not smaller than 0 to not larger than P-1. A second transmission means transmits a random exponent D to a station to be verified. A first processing means forms the product of authentication information exponentiated by a random number (r) and the exponent D within the ring of integers of a modulo N as a marker (t). The first transmitting means is constituted also so as to transmit the marker (t) to the verification station. Then, the second processing means confirm authentication information by verifying an equation having a coefficient N, a number of public power P, the marker (t), the random exponent D, a shaded identifier J and a title T as variables.
QUISQUATER JEAN-JACQUES
TELEDIFFUSION FSE
KONINKL PHILIPS ELECTRONICS NV