Yannis Soupionis, George Tountas, Dimitris Gritzalis. Audio CAPTCHA for SIP-Based VoIP. In Dimitris Gritzalis, Javier López, editors, Emerging Challenges for Security, Privacy and Trust, 24th IFIP TC 11 International Information Security Conference, SEC 2009, Pafos, Cyprus, May 18-20, 2009. Proceedings. Volume 297 of IFIP, pages 25-38, Springer, 2009. [doi]
Abstract is missing.