| 摘要 |
In a data processing device (DTD), a first key (K1) is produced based on a secret key (K) so that the latter is never used in clear. In a preliminary step, the secret key (K) and a random number (R1) are applied (I2) to a function (F1) producing the first key (K1). The first key and the random number are pre-stored (I3) in the device. For example, for each data (BD) processing (ET), the first key and another random number (R2) are applied (E2) to another function (F2) to produce a second key (K2), and the second key and the stored number (R1) are applied (E3) as inverse (F1<-1>) of the function (F1) to produce a third key (K3) used for processing the data, properly speaking. The device can be a smart card and the data the confidential code presented to the card. |
