Scaffolding and update problem

Rails
1

I have the following code…

I use the standard code generate by script/generate scaffold …

def update
@ftpuser = Ftpuser.find(params[:id])

 #
 @ftpuser.Password = md5(@ftpuser.Password)
 #

 if @ftpuser.update_attributes(params[:ftpuser])
   flash[:notice] = 'FTP-Benutzer erfolgreich akualisiert.'
   redirect_to :action => 'show', :id => @ftpuser
 else
   render :action => 'edit'
 end
 .
 .

end

def md5(passwort)
hash_class = Digest::MD5
@md5_passwort = hash_class.hexdigest(passwort)
end

My intention is to md5 the cleartext entered Password in a form -
but I have no access. The password is stored still in cleartext.

Any hints?

Thanx

–
Jochen