Increased design complexity, shrinking design cycle, and low costthis three-dimensional demand mandates advent of system-on-chip (SoC) methodology in semiconductor industry. The key concept of SoC is reuse of the intellectual property (IP) cores. Reuse of IPs on SoC increases the risk of misappropriation of IPs due to introduction of several new attacks and involvement of various parties as adversaries. Existing literature has huge number of proposals for IP protection (IPP) techniques to be incorporated in the IP design flow as well as in the SoC design methodology. However, these are quite scattered, limited in possibilities in multithreat environment, and sometimes mutually conflicting. Existing works need critical survey, proper categorization, and summarization to focus on the inherent tradeoff, existing security holes, and new research directions. This paper discusses the IP-based SoC design flow to highlight the exact locations and the nature of infringements in the flow, identifies the adversaries, categorizes these infringements, and applies strategic analysis on the effectiveness of the existing IPP techniques for these categories of infringements. It also clearly highlights recent challenges and new opportunities in this emerging field of research. © 2011 Debasri Saha and Susmita Sur-Kolay.