standards

Databases require robust protection against unauthorized access, primarily managed through Access Control Lists (ACL) using commands like GRANT and REVOKE. Challenges arise when attackers gain direct access to database files, especially if backups are stored insecurely or if databases are hosted in the cloud. Encrypting backups is common but can be cumbersome, particularly with large data volumes. If attackers access the file system, they may bypass SQL access altogether. Client-side encoding, such as using PostgreSQL's pgcrypto, protects sensitive data by encoding it before storage, but it faces challenges like key management, lack of SQL filtering, and the need for query rewrites. Transparent Data Encryption (TDE) allows SQL operations to function normally while keeping data unreadable on disk. Various TDE implementations exist, including Percona's initial TDE, which faced issues with unprotected indexes and performance slowdowns. Cybertec and EnterpriseDB encrypt entire clusters, simplifying the process but impacting performance and complicating technical support. Selective encryption approaches from Pangolin and Fujitsu allow for protecting specific tables, while Percona's recent TDE implementation also follows this model but lacks support for non-standard Table Access Methods (TAMs). Postgres Pro Enterprise TDE addresses key rotation and time-based analysis protection by storing a key index for each table page and using random initialization vectors and Message Authentication Codes for enhanced security. Future developments aim to improve TDE capabilities, including protecting compressed tablespaces and refining WAL data encryption.