In the context of data security, encryption plays a critical role in protecting digital information both at rest and in transit from unauthorized access, corruption, or theft. Encryption at rest ensures that data stored on disks is secure, using tools like FileVault for Mac OS users, while encryption in transit protects data during transmission, exemplified by HTTPS. AWS Key Management Service (KMS) facilitates encryption by generating, storing, and managing encryption keys, ensuring secure data handling across AWS services. It supports encryption at rest and in transit, crucial for compliance with standards like PCI DSS. HashiCorp Vault complements KMS by focusing on secrets management and identity-based access, offering features like dynamic credential generation and encryption as a service. Together, these tools enhance security but require automated mechanisms to mitigate human errors and ensure robust data protection, highlighting the importance of integrating security practices into DevSecOps workflows.