BSI C5 · Control CRY-04 · Priority: high · Component: Cryptography & Key Management

What this control covers

Implements secure key management for generation, storage, distribution, and deletion, separating key systems from applications. Specifies handling of compromised keys and pre-shared key provisions, protecting cloud customer data encryption integrity.

Why it matters

Encryption and key management make data unreadable to attackers and unintelligible under data-breach safe-harbour clauses — a meaningful regulatory benefit.

How to implement

AWS

Default to SSE-KMS with customer-managed keys for S3/EBS/RDS/Secrets Manager. Use S3 Bucket Keys and S3 Block Public Access at the account level, and turn on S3 Object Lock on backup buckets for ransomware resilience.

Azure

Store secrets in Key Vault (HSM-backed where required) with soft-delete + purge protection; use customer-managed keys for Storage, SQL, and Azure Disk Encryption. Tag PII data via Microsoft Purview.

GCP

Use Cloud KMS with customer-managed encryption keys (CMEK) for BigQuery, GCS, and Compute. Sensitive Data Protection (DLP API) inspects/de-identifies PII at scale.

Google Workspace

Enable client-side encryption for Drive/Docs and turn on Drive Labels + DLP rules to prevent external sharing of regulated data classes.

Evidence to collect

  • infra_scan — See the iCompaas Evidence library for the canonical source for this evidence type.

Infrastructure posture tooling (AWS Config, Azure Policy, Nessus) verifies platform hardening. Focus: Secure key management.

Quick checklist

  • Security — Protection / - Configuration
  • Protection — Protection / - Configuration
  • Data — Protection / - Configuration
  • Encryption — Protection / - Configuration
  • Secure — Protection / - Configuration

Related articles on this site