TY - CONF JO - Security and Privacy, 2000. S&P 2000. Proceedings. 2000 IEEE Symposium on TI - Using conservation of flow as a security mechanism in network protocols T2 - Security and Privacy, 2000. S&P 2000. Proceedings. 2000 IEEE Symposium on IS - SN - VO - SP - 132 EP - 141 AU - Hughes, J.R. AU - Aura, T. AU - Bishop, M. Y1 - 2000 PY - 2000 KW - computer networks KW - protocols KW - security of data KW - telecommunication security KW - WATCHERS algorithm KW - conservation of flow KW - denial of service attacks KW - misbehaving routers KW - network protocol security VL - JA - Security and Privacy, 2000. S&P 2000. Proceedings. 2000 IEEE Symposium on DOI - 10.1109/SECPRI.2000.848451 AB - The law of conservation of flow, which states that an input must either be absorbed or sent on as an output (possibly with modification), is an attractive tool with which to analyze network protocols for security properties. One of its uses is to detect disruptive network elements that launch denial of service attacks by absorbing or discarding packets. Its use requires several assumptions about the protocols being analyzed. We examine the WATCHERS algorithm to detect misbehaving routers. We show that it uses conservation of flow without sufficient verification of its assumptions, and can consequently be defeated. We suggest improvements to make the use of conservation of flow valid ER -