| 摘要 |
In a method for the protection and checking of documents protected against imitation, falsification and misuse, the document is provided with an integrated circuit with a memory which is inaccessible from the outside. Use is made of pairs of algorithms or allocated codes based on trap-door functions, one of which is kept secret whilst the other does not require to be kept secret. Information is coded by means of the algorithm kept secret or the code allocated to it. The coded information is decoded using the algorithm or code which does not require to be kept secret. The decoded and uncoded information is compared, and the result of the comparison indicates the validity of the document. In order to protect the document, the algorithm kept secret or the associated code is stored in the document memory which is inaccessible from the outside. For the check a random number is coded by means of the algorithm kept secret or the allocated code in the integrated circuit for the document. The coded random number is decoded by means of the algorithm which does not require to be kept secret, or the associated code, and compared with the original random number. |
