AWS Certified Solutions Architect – Professional — Question 22

You are designing a photo-sharing mobile app. The application will store all pictures in a single Amazon S3 bucket.
Users will upload pictures from their mobile device directly to Amazon S3 and will be able to view and download their own pictures directly from Amazon S3.
You want to configure security to handle potentially millions of users in the most secure manner possible.
What should your server-side application do when a new user registers on the photo-sharing mobile application?

Answer options

• A. Create an IAM user. Update the bucket policy with appropriate permissions for the IAM user. Generate an access key and secret key for the IAM user, store them in the mobile app and use these credentials to access Amazon S3.
• B. Create an IAM user. Assign appropriate permissions to the IAM user. Generate an access key and secret key for the IAM user, store them in the mobile app and use these credentials to access Amazon S3.
• C. Create a set of long-term credentials using AWS Security Token Service with appropriate permissions. Store these credentials in the mobile app and use them to access Amazon S3.
• D. Record the user's information in Amazon RDS and create a role in IAM with appropriate permissions. When the user uses their mobile app, create temporary credentials using the AWS Security Token Service "AssumeRole" function. Store these credentials in the mobile app's memory and use them to access Amazon S3. Generate new credentials the next time the user runs the mobile app.
• E. Record the user's information in Amazon DynamoDB. When the user uses their mobile app, create temporary credentials using AWS Security Token Service with appropriate permissions. Store these credentials in the mobile app's memory and use them to access Amazon S3. Generate new credentials the next time the user runs the mobile app.

Correct answer: E

Explanation

The correct answer is E because it utilizes Amazon DynamoDB for user information storage and provides temporary credentials through AWS Security Token Service, which enhances security by limiting the duration of access. Options A and B use long-term credentials, which can pose a security risk if compromised. Option C also uses long-term credentials, and options D, while using temporary credentials, rely on Amazon RDS instead of using DynamoDB, making E the most secure choice.