A company wants to grant an external vendor temporary, limited access to an Amazon S3...

Amazon S3 presigned URLs are the most secure fit because they providetime-limited access to specific objectswithout requiring the external vendor to have AWS credentials or direct bucket permissions. AWS documentation states that presigned URLs grant temporary access to private S3 objects and can be used for downloads through a browser or program. This is stronger than creating an IAM user or sharing temporary keys because those methods still expose AWS credentials to a third party. A bucket policy based only on source IP is broader and less precise than object-level, time-bounded access. Presigned URLs let the company control exactlywhich objectcan be downloaded andfor how long, which is exactly what the scenario requires. (AWS Documentation)

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