Interview Questions/Technical Deep Dive/KMS and Envelope Encryption Design
AdvancedTechnical
5 min

KMS and Envelope Encryption Design

SecurityEncryptionCloud
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Interview Question

Explain how you would design application-layer encryption using a cloud KMS and envelope encryption for sensitive data.

Key Points to Cover
  • Use KMS to manage CMKs; generate DEKs for data encryption
  • Encrypt data with DEK; store encrypted DEK alongside ciphertext
  • Rotate CMKs and re-encrypt DEKs (not bulk data) periodically
  • Audit key usage and enforce IAM least privilege
  • Handle performance with caching and envelope patterns
Evaluation Rubric
Describes envelope encryption pattern correctly35% weight
Explains key rotation and auditing25% weight
Secures KMS access via IAM20% weight
Addresses performance and caching20% weight
Hints
  • 💡Separate keys by data domain and environment.
Potential Follow-up Questions
  • How do you handle multi-region key availability?
  • What about client-side vs server-side encryption?
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