A Practice Note providing an overview of encryption concepts and techniques. This Note discusses how encryption works and common threats and pitfalls to its successful implementation and use as a data security measure and privacy-enhancing technology (PET), including cyberattacks and key management and quantum computing risks. It also contrasts encryption with anonymization, other forms of pseudonymization, and hashing (with salting) and discusses specialized and emerging encryption forms, such as lightweight protocols and privacy-enhancing cryptography (PEC) techniques like fully homomorphic encryption.