# BSI C5 CRY-04 — Secure key management

- Source: https://support.icompaas.com/support/solutions/articles/a_gen_bsic5_cry04_37868ce588-bsi-c5-cry-04-secure-key-management
- Section: [Solutions](https://support.icompaas.com/support/solutions) › [BSI C5 (German Cloud)](https://support.icompaas.com/support/solutions/c_gen_bsi_c5) › [Cryptography & Key Management](https://support.icompaas.com/support/solutions/folders/f_gen_cgenbsic5_cryptographykeymanagement)
- Last updated: 2026-05-30
- Publisher: iCompaas, Inc. (https://www.icompaas.com)

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

-   [Microsoft Cloud Security Posture Management (CSPM)](https://support.icompaas.com/support/solutions/articles/62000234105-microsoft-cloud-security-posture-management-cspm-)
-   [NIST 800-171 3.4.2 Establish and enforce security configuration settings for information technology products employed in organizational systems.](https://support.icompaas.com/support/solutions/articles/62000229281-nist-800-171-3-4-2-establish-and-enforce-security-configuration-settings-for-information-technology-p)
-   [CMMC 2.0 CM.2.064 Establish and enforce security configuration settings for information technology products employed in organizational systems.](https://support.icompaas.com/support/solutions/articles/62000229466-cmmc-2-0-cm-2-064-establish-and-enforce-security-configuration-settings-for-information-technology-pr)
-   [Ensure KMS keys with key rotation is not disabled](https://support.icompaas.com/support/solutions/articles/62000127090-ensure-kms-keys-with-key-rotation-is-not-disabled)

## Related compliance guidance

- [SOC 2 compliance: a practical implementation guide for cloud-native SaaS teams](https://support.icompaas.com/compliance/soc-2-trust-services-criteria): Configuration checks like this one are the technical half of a SOC 2 / ISO 27001 programme — the guide shows where they fit, what else an auditor expects, and how to evidence them.
- [ISO/IEC 27001:2022 compliance: a practical implementation guide](https://support.icompaas.com/compliance/iso-27001-2022): ISO 27001 Annex A.8 (technological controls) is where cloud hardening evidence lands; the guide shows how to run the ISMS around it.