Quick Answer
The answer is Customer Lockbox for Azure Storage. This feature is correct because it enforces a mandatory approval workflow before Microsoft engineers can access your storage data for support requests, and when combined with customer-managed keys (CMK) stored in Azure Key Vault, revoking those keys renders the data permanently inaccessible—even to Microsoft—unless you explicitly consent. On the Microsoft Azure Solutions Architect Expert AZ-305 exam, this scenario tests your understanding of defense-in-depth and data sovereignty controls, often appearing as a distractor against features like Azure RBAC or service endpoints. A common trap is confusing Customer Lockbox with Azure Policy or just enabling CMK alone; remember that CMK prevents Microsoft from decrypting data without your key, but Lockbox prevents them from even attempting to access the storage account. Memory tip: think of Lockbox as a “human gate” for your encrypted vault—without your key, the data is locked; without your approval, the door stays shut.
This AZ-305 practice question tests your understanding of design data storage solutions. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company needs to store sensitive customer data in Azure Blob Storage. They require encryption at rest using customer-managed keys (CMK) stored in Azure Key Vault. Additionally, they want to prevent data from being accessed if the key is revoked. Which feature should they enable?
Azure Defender for Storage
Why wrong: Defender is for security monitoring, not key-based access control.
Customer Lockbox for Azure Storage
Customer Lockbox enables you to control access with key revocation, blocking data access.
Azure Files with AD DS authentication
Why wrong: This is for file shares, not Blob storage.
Storage Service Encryption (SSE)
Why wrong: SSE uses Microsoft-managed keys, not customer-managed.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Customer Lockbox for Azure Storage
Customer Lockbox for Azure Storage provides an additional layer of control by requiring explicit approval from the customer before Microsoft engineers can access storage data for support or troubleshooting. When combined with customer-managed keys (CMK) in Azure Key Vault, revoking the key renders the data inaccessible, and Customer Lockbox ensures that even Microsoft cannot bypass this protection without your consent.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Azure Defender for Storage
Why it's wrong here
Defender is for security monitoring, not key-based access control.
Customer Lockbox for Azure Storage
Why this is correct
Customer Lockbox enables you to control access with key revocation, blocking data access.
Related concept
Read the scenario before looking for a memorised answer.
Azure Files with AD DS authentication
Why it's wrong here
This is for file shares, not Blob storage.
Storage Service Encryption (SSE)
Why it's wrong here
SSE uses Microsoft-managed keys, not customer-managed.
Common exam traps
The trap here is that candidates often confuse Customer Lockbox with Azure Defender for Storage or SSE, assuming that encryption alone prevents access, but only Customer Lockbox provides the explicit approval gate for Microsoft support access after key revocation.
Detailed technical explanation
Customer Lockbox works by intercepting support requests that require direct access to storage data, routing them through an approval workflow in the Azure portal. When a CMK is revoked, the storage account's encryption key becomes unavailable, making the data unreadable; Customer Lockbox ensures that even Microsoft support engineers cannot bypass this by requiring explicit customer approval for any access attempt. This is particularly critical in regulated industries like finance or healthcare, where data sovereignty and audit trails are mandatory.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
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FAQ
Design data storage solutions — This question tests Design data storage solutions — Read the scenario before looking for a memorised answer..
The correct answer is: Customer Lockbox for Azure Storage — Customer Lockbox for Azure Storage provides an additional layer of control by requiring explicit approval from the customer before Microsoft engineers can access storage data for support or troubleshooting. When combined with customer-managed keys (CMK) in Azure Key Vault, revoking the key renders the data inaccessible, and Customer Lockbox ensures that even Microsoft cannot bypass this protection without your consent.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
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.
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