Control of access to data processing installation, uses transformation of entered code and stored access code so comparison is carried out on transformed rather than actual codes

摘要

Access to a functionality of a smart card is through entry of a secret access code (CS), which is preprocessed (E2) to generate a transformed secret code (CST). The internally stored version of the access code is also transformed (E6), and the comparison process that may be observed by energy consumption attack is performed on the transformed codes, so only the transformed code can be detected.