It is our great pleasure to welcome you to the 3rd Workshop on Cyber-Security Arms Race (CYSARM)! This year we are thrilled to continue chairing this workshop at a prestigious venue as the ACM Conference on Computer and Communications Security (CCS). Although CYSARM is at the early phases (this year marks the third edition of this workshop), the workshop is already fostering collaboration among researchers and practitioners to discuss the various facets and trade-offs of cyber-security. Being the first workshop of its kind, CYSARM benefits the cyber-security community by addressing novel (and often controversial) topics in cyber-security, such as trade-offs and double-edged sword techniques. Beyond the study of cyber-security, privacy and trust as standalone components, it is also important to look at how to balance their trade-offs especially when it comes to several contradicting requirements, such as security vs privacy, security vs trust, and security vs usability. CYSARM considers all complex facets and double-edged sword aspects of the cyber-security ecosystem, in particular, how new technologies and algorithms might impact the cyber-security of existing or future models and systems.