Manufacturer independent, authenticity identification device obtaining method for service provider - involves storing code, from service provider, obtained by RSA function having secret encryption key, in write-once type area of card

摘要

The method involves using an identification device (1) provided with only one read-only area (2) which is writable only at the manufacturing time, and at least one writable area (3), the one read only area and the at least one writable area being freely externally readable by an external device. A first permanent and unique code (5) is applied to the read-only area by the manufacturer of the identification device at the manufacturing time, the first permanent and unique code being freely externally readable. A service provider then applies to the at least one writable area a freely externally readable second code (7), which is obtained by computing, by an RSA encryption function having a secret encryption key (8), the joining in predetermined positions of the first permanent unique code and of a message (6). The identification device is externally validated through decryption of the second code by a decryption key (9), a portion of the decrypted second code arranged in a predetermined position being compared with the first permanent and unique code to verify the authenticity of the identification device and of the message applied to the at least one writable area.