Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
A company uses a customer managed AWS KMS key to encrypt sensitive data stored in DynamoDB. A Lambda function reads from the DynamoDB table and needs to decrypt the data. The Lambda function's execution role has an IAM policy that allows kms:Decrypt on the key. However, access is denied. What must the developer add to the KMS key policy to resolve the issue?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
Add a statement granting kms:Decrypt to the Lambda function's execution role.
Correct. The key policy must explicitly allow the IAM role to perform kms:Decrypt.
B
Distractor review
Add a statement granting kms:Decrypt to the Lambda function's resource-based policy.
Lambda functions do not have resource-based policies for KMS; the key policy is the resource policy.
C
Distractor review
Add a statement granting kms:Decrypt to the Lambda service principal.
The service principal is not the entity that accesses the key; the execution role does.
D
Distractor review
Add a statement granting kms:Decrypt to the account root user with a condition for the Lambda function.
While the root user can delegate access via IAM, a condition on the root is not a secure or direct way to grant the Lambda role.
Common exam trap
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Technical deep dive
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Related practice questions
Related DVA-C02 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A developer is building a REST API using Amazon API Gateway that will serve static content from an Amazon S3 bucket. The API should cache responses for frequently accessed objects to reduce latency. Which API Gateway feature should the developer enable?
Question 2
A developer is running a web application on multiple Amazon EC2 instances behind an Application Load Balancer (ALB). The application needs to store user session state that must be available across all instances. The session data is small and temporary but must survive individual instance failures. Which AWS service should the developer use to store this session state?
Question 3
A developer has an AWS Lambda function that processes messages from an Amazon SQS standard queue. The function is idempotent and currently has a batch size of 10. The developer wants to increase throughput and increases the batch size to 100. After the change, CloudWatch metrics show a significant increase in throttles and the queue backlog is growing. The function's reserved concurrency is set to 10. What is the most effective action to resolve the throttling and improve throughput?
Question 4
A developer is managing an application running on Amazon EC2 instances behind an Application Load Balancer. Users report that the application becomes unresponsive after several hours, and restarting the instance temporarily fixes the issue. The developer suspects a memory leak but cannot add custom instrumentation. Which AWS service can collect memory utilization metrics and help identify the memory leak with minimal configuration?
Question 5
A developer is building a serverless web application using AWS Lambda and Amazon DynamoDB. The application needs to perform complex aggregations on data stored in DynamoDB. Which AWS service should the developer use to perform these aggregations efficiently without reading all the data into Lambda?
Question 6
A developer has an Amazon S3 bucket containing private user documents. The application must generate a time-limited URL for users to download their own documents without requiring the users to have AWS credentials. Which solution should the developer use?
FAQ
Questions learners often ask
What does this DVA-C02 question test?
Read the scenario before looking for a memorised answer.
What is the correct answer to this question?
The correct answer is: Add a statement granting kms:Decrypt to the Lambda function's execution role. — AWS KMS key policies are resource-based policies that control who can use the key. Even if an IAM policy grants a principal permission, the key policy must explicitly allow that principal to use the key (unless the key policy grants access to the account root, which then delegates to IAM). By default, KMS key policies do not grant access to any IAM roles except the root user. Therefore, to allow the Lambda execution role to decrypt, the key policy must include a statement granting the role the necessary permissions.
What should I do if I get this DVA-C02 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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