sqlplus.exe and passwords in cleartext

Hi, we have some batch scripts which requires to login into the Oracle database using sqlplus.

Unfortunately the scripts have the password in cleartext stored:

sqlplus username/password@database

for security reason we need to make it more secure. Currently we have a textfile which sored all the information, so we can source it at the beginnig of our script, then just use variables.

Is there any chance to use a local passwordfile which stores the username/password encrypted on the client? so the loginstring would look like

sqlplus username/passwordfile@database or however

How are other systems handle this security issue on windows systems?