1Multi-Factor AuthenticationMulti-factor authentication adds independent proof to a login, making stolen passwords far less useful to attackers.Identity and Crypto 2Public-Key Crypto and CertificatesHow public and private keys let strangers communicate safely, and how certificates turn keys into identities you can trust.Identity and Crypto 3Phishing and Social EngineeringPhishing succeeds by manipulating trust, timing, and habit, so good defense must combine people, process, and technical controls.Identity and Crypto 4Malware and RansomwareMalware is software turned against its owner; ransomware is the business model that makes digital extortion scale.Identity and Crypto 5Network Security BasicsNetwork security is the practice of controlling who can connect, what can move, and how quickly you notice when something goes wrong.Identity and Crypto