HashiCorp Vault provides a defense-in-depth encryption strategy to secure data in Microsoft SQL Server by extending transparent data encryption (TDE) capabilities. TDE protects sensitive data at rest by encrypting it with a data encryption key (DEK), and HashiCorp Vault's EKM module manages the security of these keys, providing an additional layer of protection against attacks such as ransomware and insider threats. With the EKM module, Vault Enterprise customers can securely store encrypted DEKs on disk, ensuring that even if an attacker gains access to the server, they still need the KEK to decrypt the data, thereby protecting sensitive customer data.