摘要 |
A data carrier device (3) includes data storage means (13) for storing key data (SD), processing means (14) for processing key data (SD), data bus means (15) which include a data bus (16) with a number of N parallel data leads which connects the data storage means (13) to the processing means (14), and via which N-bit key data (SD) can be transmitted in parallel during each transmission operation, and power supply means (E) for supplying the data carrier device (3) with power (UB); transmission data (ÜD-SD), containing key data (SD), can be stored in the data storage means (13) and the data bus means (15) are arranged to transmit N-bit transmission data (ÜD-SD) in each transmission operation, which transmission data (ÜD-SD) has a number of M bits of value 1 which is always the same and independent of the key data (SD); the data bus means (15) have a power consumption which is independent of the key data (SD) and include selection means (29, 31) which are arranged to select, after a transmission operation, a number of K bits, constituting the key data (SD), from the total number of N transmitted bits of the transmission data (ÜD-SD).
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