Patent ID: 8452977

Claim:
A method for generating a first key to encode and/or decode data and a first pointer, with said data stored in an encoded form and/or storable in an encoded form on a first data processing system in a memory area identified by said first pointer, comprising the following steps: recursive generating of said first key from a second key, recursive generating of said first pointer from a second pointer, with the number of recursions for implementing the recursive generating of said first key and said first pointer determined by an index value, with generating said first key and generating said first pointer carried out by a processor of a portable data carrier, with the index value increased by one for data to be newly stored, and with said new index value stored on said portable data carrier, with storing said data in the first data processing system comprising the following steps: encoding or decoding said data with the recursively generated first key by means of a second data processing system, and storing or querying said encoded data in or by the memory area of the first data processing system by means of said second data processing system, said memory area identified by the recursively generated first pointer, wherein the recursive generating of said first key from the second key and the recursive generating of said first pointer from the second pointer comprising the following steps: generating said first key by using the second key and a third key, generating said first pointer by using the second pointer and a fourth key, and the following additional steps being repeated as frequently as the number that corresponds to the index value: newly generating the first key by using the previously generated first key and the second key, newly generating the first pointer by using the previously generated first pointer and the fourth key.