摘要 |
A method for authenticating a portable data carrier (10) to a terminal device by the following steps: In the data carrier (10) a public session key (PKSession) is derived (S5) from a public key individual to the data carrier (PKi) which has in its turn been derived (TS32; S1) from a public group key (PK). Further, a secret session key (SKSession) is derived (S4) from a secret key individual to the data carrier (SKi) which has in turn been derived (TS31) from a secret group key (SK). Subsequently, a secret communication key (KK) is agreed on (S7) between the data carrier (10) and the terminal device. Finally, the terminal verifies (S8) the public session key (PKSession) of the data carrier (10).
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