AZ-204 Implement Azure security Practice Question
Your organization has a custom application that stores customer data in Azure Cosmos DB. You need to encrypt the data at rest using a customer-managed key stored in Azure Key Vault. Which type of Cosmos DB encryption should you configure?
⚠ Common exam trap
It's easy for candidates to confuse client-side encryption (which encrypts data before transmission) with server-side encryption at rest using CMK, leading candidates to select Option D instead of the correct server-side CMK configuration.
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
✓
Use customer-managed keys (CMK) with Azure Key Vault
Azure Cosmos DB supports customer-managed keys (CMK) integrated with Azure Key Vault to encrypt data at rest. This allows you to bring your own key (BYOK) and control key rotation, revocation, and access policies, meeting the requirement for a customer-managed key stored in Azure Key Vault.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Enable Azure Disk Encryption on the Cosmos DB instance
Why it's wrong here
Azure Disk Encryption (ADE) is a feature designed to encrypt the OS and data disks used by Azure Virtual Machines (VMs) and VM Scale Sets. It leverages industry-standard BitLocker for Windows and DM-Crypt for Linux to provide volume encryption. Since Azure Cosmos DB is a fully managed Platform-as-a-Service (PaaS) offering, users do not have direct access to or control over the underlying virtual machines or their disks, making ADE an inapplicable solution for encrypting Cosmos DB data at rest.
- ✗
Enable Transparent Data Encryption (TDE)
Why it's wrong here
Transparent Data Encryption (TDE) is a feature primarily associated with Microsoft SQL Server, Azure SQL Database, and Azure Synapse Analytics, providing encryption of data files at rest for relational databases. While TDE encrypts the entire database, log files, and backups, it is not a native or supported encryption mechanism for Azure Cosmos DB. Cosmos DB, being a NoSQL database service, employs its own distinct, platform-managed encryption-at-rest capabilities by default.
- ✓
Use customer-managed keys (CMK) with Azure Key Vault
Why this is correct
Azure Cosmos DB inherently encrypts all data at rest using service-managed keys, but for enhanced security and compliance requirements, it supports customer-managed keys (CMK). By integrating with Azure Key Vault, customers can provide their own encryption keys, gaining full control over the key lifecycle, including rotation, revocation, and auditing. This ensures that even Microsoft cannot access the data without the customer's explicit key, fulfilling stringent data governance policies.
- ✗
Implement client-side encryption using the SDK
Why it's wrong here
Client-side encryption involves encrypting data within the application code *before* it is sent to the database, meaning the data is already encrypted when it reaches Azure Cosmos DB. While this provides an additional layer of security by ensuring data is encrypted in transit and at rest within the database, it shifts the key management responsibility entirely to the application developer. This approach differs from database-level encryption at rest, which focuses on securing the storage layer of the database service itself, often using service-managed or customer-managed keys.
Go deeper
Related to this question
About these practice questions
This AZ-204 question is part of Courseiva's 881-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-204 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-204 exam.