[Dovecot] Is the users password available from a mail_filter?

Hi,

I'm working on a Dovecot encryption module which uses the mail filter plugin to encrypt/decrypt the message "on the fly". I was wondering whether it is possible to access the password (or a hashed password) of the user. It seems that only the user (using the %u parameter) is available to the mail_filter plugin. Any idea how to get hold of the (possibly hashed) password?

Kind regards,

Martijn Brinkers