Backup security and encryption encompasses the practices and technologies for protecting backup data from unauthorized access, tampering, and destruction throughout its lifecycle. This includes encrypting backup media, securing backup infrastructure, controlling access to restoration capabilities, and ensuring backup integrity through verification and monitoring.
Backup encryption operates at multiple levels. Client-side encryption encrypts data before transmission to the backup target, ensuring the backup service or storage never receives plaintext. Server-side encryption encrypts data at the backup repository using keys managed by the backup platform or an external KMS. Tape encryption uses hardware-based AES-256 encryption in tape drives with keys managed through key management interoperability protocol (KMIP) servers. Backup security extends beyond encryption to include access controls that separate backup operators from restore operators, network segmentation isolating backup infrastructure, integrity verification using cryptographic checksums, and monitoring for anomalous backup patterns (sudden volume changes, unexpected deletions, or unauthorized restore operations). Immutability features -- object lock in cloud storage, WORM compliance in tape libraries -- prevent backup modification or deletion even by administrators.
Backups are frequently the least secured copy of an organization's most sensitive data. Ransomware groups specifically target backup infrastructure to prevent recovery, with groups like Conti and LockBit documenting backup destruction in their playbooks. Unencrypted backup tapes have caused major breaches when lost in transit -- the US Veterans Affairs Department lost unencrypted backup tapes containing records of 26.5 million veterans. Compliance frameworks including PCI DSS, HIPAA, and SOX require backup encryption and access controls equivalent to production systems.
CDA addresses backup security within the Data Protection and Sovereignty domain as a C-BUILD to C-HARDEN deliverable. Our missions audit backup encryption coverage, implement immutable backup architectures, establish backup access governance, and conduct backup-focused penetration testing to validate resilience against ransomware actors.