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Security and privacy at the application level include TLS for authentication, confidentiality, and integrity; certificate authorities and Web PKI underpin trust but introduce centralization and failure modes. Computer Networks Tanenbaum Slides
Threats: eavesdropping, message tampering, spoofing, DoS/DDoS, routing attacks (BGP hijacks), DNS poisoning. Defenses include: Not all slides are created equal
Guided media (fiber optics, coaxial cable, twisted pair) versus wireless media (radio, microwave, infrared). routing attacks (BGP hijacks)