WRITEKEY [--force] keyid
This command is used to store a secret key on a a smartcard.  The
allowed keyids depend on the currently selected smartcard
application. The actual keydata is requested using the inquiry
KEYDATA and need to be provided without any protection.  With
--force set an existing key under this keyid will get
overwritten.  The key data is expected to be the usual canonical encoded
S-expression.
   
A PIN will be requested in most saes. This however depends on the actual card application.