| 摘要 |
<p>Product indicia for use in authenticating products or as tax stamps are generated and encrypted with a public encryption key. The encrypted indicia are then transferred (e.g. via modem) to an indicia application location (152) where the indicia are to be applied to products (e.g. by printer 160). The encrypted indicia are decrypted at the application location using the corresponding private key. However, this private key, stored at the application location (in key file 164), is itself encrypted with a code-protected key which is embedded in a code-protected processor device (158). The code-protected key cannot be deciphered without rendering the code-protected memory inoperable. An encrypted log file (166) is also maintained of product indicia which have been processed previously. Decrypted indicia which are ready for printing are compared to indicia in the log file to ensure that these indicia have not been printed before.</p> |
