AZ-305 Design infrastructure solutions Practice Question
You are designing a solution to store sensitive documents in Azure Blob Storage. The data must be encrypted at rest and access must be audited. You need to ensure that the encryption keys are managed by your organization and that access to the keys is logged. Which combination of Azure services should you use?
⚠ Common exam trap
Candidates often confuse Azure Disk Encryption (which encrypts VM disks) with Azure Storage encryption (which encrypts blob data), leading them to select Option B despite it not addressing blob storage encryption or audit logging requirements.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Azure Storage encryption with customer-managed keys in Azure Key Vault and Azure Monitor
Azure Storage encryption with customer-managed keys in Azure Key Vault meets the requirement for organization-managed encryption keys, while Azure Monitor (specifically the Azure Activity Log or diagnostic settings) captures access logs for both the storage account and Key Vault operations, enabling full auditability of key usage and data access.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Azure Storage encryption with customer-managed keys in Azure Key Vault and Azure Monitor
Why this is correct
Azure Storage encryption always encrypts data at rest, but with customer-managed keys (CMK) in Azure Key Vault, you control key rotation, permissions, and lifecycle, which is essential for sensitive documents. Enabling Key Vault diagnostics and routing those logs to Azure Monitor provides auditable access trails, letting you detect unauthorized key usage. This combination meets compliance requirements that demand both cryptographic control and monitoring.
- ✗
Azure Disk Encryption with Azure Key Vault
Why it's wrong here
Azure Disk Encryption uses BitLocker (Windows) or DM-Crypt (Linux) to encrypt the OS and data disks of virtual machines, not Azure Blob Storage. Since you are storing documents as blobs, this service is architecturally irrelevant—it would only apply if the documents sat on a VM's managed disks. For blob data, you must rely on storage-level encryption, not VM disk encryption.
- ✗
Azure Storage encryption with Microsoft-managed keys and Azure Monitor
Why it's wrong here
While Azure Storage encryption is always enabled, Microsoft-managed keys operate without your intervention, meaning you cannot control key lifecycle, rotation, or access permissions. Auditing with Azure Monitor under this model captures storage operations but not granular key-level usage, which often fails regulatory requirements for sensitive documents. Moreover, without key ownership, you cannot prove that encryption keys have not been exposed.
- ✗
Azure Information Protection and Azure Sentinel
Why it's wrong here
Azure Information Protection (AIP) classifies and labels documents based on sensitivity, while Azure Sentinel is a SIEM/SOAR tool for detecting security threats. Neither performs encryption-at-rest for Azure Blob Storage—AIP does not encrypt the underlying data at rest, and Sentinel only aggregates logs. Sensitive documents require encryption of the storage layer itself; classification and monitoring are complementary, not replacements.
Quick reference
Azure Blob Storage Tier Comparison
| Tier | Storage Cost | Retrieval Cost | Latency | Use Case |
|---|---|---|---|---|
| Hot | Highest | Lowest | Immediate | Active data, frequent reads |
| Cool | Lower | Higher | Immediate | Data accessed < once / month |
| Cold | Lower still | Higher | Immediate | Data accessed < once / quarter |
| Archive | Lowest | Highest + rehydration delay | Hours | Long-term compliance retention |
Go deeper
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-305 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the AZ-305 exam.