Secure data transaction implementation with a chip card, whereby a partial data transaction is carried out by the chip card using a secure secondary data element prior to linking with transaction data in the main processing unit

摘要

Method for carrying out a data transaction with a transaction device (18) that comprises main and separable auxiliary components. At least one partial transaction of the data transaction is carried out by the auxiliary component (40) using a secondary data element that is stored in the auxiliary component and is inaccessible to spying methods. The secondary data element is transferred into the main component (20) that also carries out a linking with the transaction data. The invention also relates to a corresponding device for method implementation with the main component configured as a software module for implementation of the data processing system.