Blocking Foxy Phishing Emails with Historical Information

Unlike most of the spams targeting for advertisements only, phishing spams try to cheat the email recipients with bogus sender addresses so as to obtain confidential information of the recipients. This paper presents a Sender Authentication Protocol (SAP) which aims to filter out this kind of crafty spoofing emails. To this end, SAP challenges the claimed-sender with the historical emails so as to verify the authenticity of the sender. As it does not change the email protocol, and is able to be embedded into the off-the-shelf email software such as Microsoft Outlook^TM, SAP is not only easy to be deployed, but also fully compatible with other anti-spam technologies. To illustrate its feasibility, we develop a SAP add-in for enhancing Microsoft Outlook^TM. The SAP add-in will be started automatically as long as Outlook is started. As the enhanced Outlook^TM has the same user interface as the original one, the add-in is transparent and friendly to the users.