File: gnupg.info,  Node: Scdaemon CHECKPIN,  Next: Scdaemon RESTART,  Prev: Scdaemon PASSWD,  Up: Scdaemon Protocol

6.6.13 Perform a VERIFY operation
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       CHECKPIN IDSTR

   Perform a VERIFY operation without doing anything else.  This may be
used to initialize a the PIN cache earlier to long lasting operations.
Its use is highly application dependent:

*OpenPGP*

     Perform a simple verify operation for CHV1 and CHV2, so that
     further operations won't ask for CHV2 and it is possible to do a
     cheap check on the PIN: If there is something wrong with the PIN
     entry system, only the regular CHV will get blocked and not the
     dangerous CHV3.  IDSTR is the usual card's serial number in hex
     notation; an optional fingerprint part will get ignored.

     There is however a special mode if IDSTR is suffixed with the
     literal string '[CHV3]': In this case the Admin PIN is checked if
     and only if the retry counter is still at 3.