Economic Evaluation of Interactive Audio Media for Securing Internet Services

Internet Telephony (Voice over Internet Protocol or VoIP) has recently become increasingly popular mainly due to its cost advantages and range of advance services. On the same time, SPam over Internet Telephony (SPIT) referred as unsolicited bulk calls sent via VoIP networks by botnets, is expected to become a serious threat in the near future. Audio CAPTCHA (Completely Automated Public Turing test to tell Computers and Human Apart) mechanism were introduced and employed as a security measure to distinguish automated software agents from human beings. The scope of this paper is to present the security economics frame and to have an in-depth review of the related economic models of SPAM and its analogies with SPIT.