| 摘要 |
The invention relates to a portable data carrier, especially a chip card, to store data in the form of data records, wherein cryptographic keys are memorized on the data carrier in order to protect the writing and reading of said data records. A series of keys is thus stored on the data carrier to perform this task. Means are provided to make the keys in the data carrier unfit for use. Also disclosed is a method for using a data carrier wherein the use of each key to read or write data is preceded by verification of whether the key is older than the key whose identification mark is stored on the data carrier. The use of said key is denied if the results of the verification are positive. |
