Which Azure Storage Deployment Supports Per-User Encryption Keys?
You plan to deploy an app that will use an Azure Storage account. You need to deploy the storage account. The storage account must meet the following requirements: ✑ Store the data for multiple users. ✑ Encrypt each user's data by using a separate key. ✑ Encrypt all the data in the storage account by using customer-managed keys. What should you deploy?
Community Insight
Tests Azure Blob Storage encryption scopes with customer-managed keys; the trap is selecting ADLS Gen2 for per-user keys despite its hierarchical namespace.
This AZ-305 storage design question asks which Azure Storage deployment can hold data for multiple users, encrypt each user's data with a separate key, and still apply an account-wide customer-managed key. The answer is blobs in a general purpose v2 storage account (B), because Blob Storage encryption scopes assign a distinct key to each container.
Most candidates choose ADLS Gen2 (C) because it is also blob storage, but encryption scopes that provide separate per-container customer-managed keys are a GPv2 blob feature; Azure Files (A and D) only supports account-level CMK, not per-share key separation.
Community Discussion (37 comments)
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Expert Analysis
Why the Answer Is Correct
The question requires three things: multi-user storage, a separate encryption key per user's data, and customer-managed keys at the storage-account level. Blobs in a general purpose v2 (GPv2) account satisfy all three because Blob Storage supports encryption scopes, which let you assign a distinct customer-managed key to each container while the account-level CMK still encrypts everything. As NotMeAnyWay notes, a GPv2 account "supports customer-managed keys for encryption," and encryption scopes are the Azure feature that delivers per-container key isolation. kay000001 and Sandeep1981 also selected B, and the Azure documentation on encryption scopes confirms that container-level keys work in GPv2 blob accounts. Option B is therefore the direct, exam-doctrine match for the stated requirements.
Why the Other Options Are Wrong
Options A and D deploy Azure Files, which does not provide separate encryption scopes or per-share customer-managed keys; Azure Files only supports account-level CMK, so it cannot encrypt each user's data with a different key. Option C deploys blobs in an Azure Data Lake Storage Gen2 account, which is a GPv2 account with hierarchical namespace (HNS) enabled. Mltytskr pointed to the Azure feature-support table and wrote that "HNS does not support customer-provided" keys, meaning the per-container key requirement is not met in the classic exam version. Backy observed that "Today, both B and C are correct answers" and AzureGeek79 argued for C, but the AZ-305 exam item is built around the GPv2 blob answer, and ADLS Gen2 adds an analytics namespace that the scenario never asks for.
Community Comment Notes
NotMeAnyWay and kay000001 both chose B, with NotMeAnyWay explaining that GPv2 supports customer-managed keys and that encryption scopes enable a separate key per user's data. Mltytskr cited the Microsoft feature-support page and noted that HNS accounts do not support customer-provided keys, which supports choosing B over C. vrm1358 and TaoLu highlighted container-level encryption scopes and metadata as the mechanism for per-user keys, reinforcing the blob-container design. Backy cautioned that current Azure support may make C valid too, but the exam answer remains B because the question tests the GPv2 blob encryption-scope model. AzureGeek79's vote for C is understandable only if you ignore the HNS limitation tested by the original item.
Exam Strategy Tip
When an AZ-305 storage question says "separate key per user" or "per-container encryption," map that immediately to Blob Storage encryption scopes in a general purpose v2 account. Eliminate Azure Files for per-share key isolation, and treat ADLS Gen2 as a hierarchical-namespace variant that the exam generally rules out for separate CMKs. Read the requirement about account-wide customer-managed keys as a confirmation that the account must support CMK, which GPv2 does.
Official Reference
Exam Strategy
Anchor on the phrase "separate key per user's data" and translate it to Blob Storage encryption scopes; that single mapping eliminates Azure Files and points to a GPv2 blob account. If two blob options remain, choose the one without hierarchical namespace because encryption scopes with customer-managed keys are tested there in AZ-305.
Frequently Asked Questions
Why is ADLS Gen2 not the answer for per-user encryption keys?
ADLS Gen2 enables a hierarchical namespace, and the exam treats encryption scopes with per-container customer-managed keys as a GPv2 blob feature; it also adds analytics overhead not required here.
How do encryption scopes give each user a separate key?
Each blob container gets its own encryption scope that references a distinct customer-managed key in Azure Key Vault, while the account-level key still encrypts all data in the storage account.
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