Bongosoft AntiSpam 2004 is a challenge based anti-spam solution, that allows you to receive email from people you know, and sends a confirmation request to all other senders. Only if the sender replies to the confirmation mail with the password included in the message, will his email go through. Once confirmed, the sender does not have to go through the procedure again, and all subsequent e-mail from that sender are passed to your inbox. To make sure that the password is not read by a machine, it is converted to an image and sent as embedded picture or attachment. Unlike most other programs of this type, Bongosoft AntiSpam works directly on the TCP level and does not require you to run a local proxy. It works fully automatically with any email program and does not require you to change any settings whatsoever. The messages that are awaiting authentication are kept in your POP box and will be deleted if they are not confirmed after a customizable number of days. Messages from known senders or that were confirmed will automatically appear in your Inbox during normal email retrieval. You can also review the queue of pending messages and manually block any sender or domain by clicking a button.