For encryption in transit, AWS Certificate Manager ACM is the correct service because it provisions and manages TLS certificates for HTTPS connections. For encryption at rest, AWS KMS is the right service because it manages encryption keys used by services such as Amazon EBS. AWS documentation and whitepapers consistently position ACM for certificate-based transport encryption and KMS for at-rest encryption key management across AWS services. GuardDuty and Shield are security detection and DDoS protection services, not encryption services. Secrets Manager stores and rotates secrets, but it is not the service used to encrypt all application data at rest or TLS sessions in transit.

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DynamoDB export to Amazon S3 (via point-in-time exports or table backups) “does not consume read capacity” and has no impact on table performance. Once data is in S3, Amazon Redshift can ingest efficiently with COPY from S3, which is the standard, parallel, high-throughput load path with minimal management. Direct COPY from DynamoDB (B) performs a table scan that can consume provisioned throughput, risking throttling. Building Lambda pipelines (C) adds custom code and scheduling overhead. Athena federated queries (D) are ad hoc analytics, not optimized for bulk, recurring warehouse loads. Therefore, exporting to S3 and loading with Redshift COPY maintains DynamoDB throughput and minimizes operational burden.

To securely integrate Amazon S3 with an application that uses Amazon Cognito for user authentication, the following two steps are essential:

Step 1: Create an Amazon Cognito Identity Pool (Option A)

Amazon Cognito Identity Poolsallow users to obtain temporary AWS credentials to access AWS resources, such as Amazon S3, after successfully authenticating with the Cognito user pool. The identity pool bridges the gap between user authentication and AWS service access by generating temporary credentials using AWS Identity and Access Management (IAM).

Once a user logs in using theCognito User Pool, the identity pool providesIAM roles with specific permissionsthat the application can use to access S3 securely. This ensures that each user has appropriate access controls while accessing the S3 bucket.

This is a secure way to ensure that users only have temporary and least-privilege access to the S3 bucket for their documents.

Step 2: Create an Amazon S3 VPC Endpoint (Option C)

By creating anAmazon S3 VPC endpoint, the company ensures that communication between the application (which is hosted in a private subnet) and the S3 bucket occurs over theAWS private network, without the need to traverse the internet. This enhances security and prevents exposure of data to public networks.

TheVPC endpointallows the application to access the S3 bucket privately and securely within the VPC. It also ensures that traffic stays within the AWS network, reducing attack surface and improving overall security.

Why the Other Options Are Incorrect:

Option B: This is incorrect becauseAmazon Cognito User Poolsare used for user authentication, not for generating S3 access tokens. To provide S3 access, you need to useAmazon Cognito Identity Pools, which offer AWS credentials.

Option D: ANAT gatewayis unnecessary in this scenario. Using aVPC endpointfor S3 access provides a more secure and cost-effective solution by keeping traffic within AWS.

Option E: Attaching a policy to restrict access based on IP addresses is not scalable or efficient. It would require managing users’ dynamic IP addresses, which is not an effective security measure for this use case.

AWS References:

Amazon Cognito Identity Pools

Amazon VPC Endpoints for S3