What purpose do S3 Pre-signed URLs serve?

S3 Pre-signed URLs allow time-limited access to specific objects stored in an Amazon S3 bucket. When a Pre-signed URL is generated, it includes a signature that grants permission to perform a specific action (like retrieving an object) for a defined period of time. This is particularly useful in scenarios where you want to share access to S3 resources without making them publicly accessible, providing a secure method of granting temporary access to controlled users.

For example, you may use a Pre-signed URL to grant a user permission to download a file without needing them to have AWS credentials. Users can access the file using the URL until it expires, which adds a layer of security and control over your S3 resources by limiting access to only those who have the link and for a limited timeframe.

Other options do not accurately represent the function of Pre-signed URLs. They do not provide permanent access; rather, they are specifically designed for temporary use. Monitoring bucket activity involves different AWS services and tools such as CloudTrail or CloudWatch, not Pre-signed URLs. Additionally, while Pre-signed URLs facilitate access, they do not inherently increase the speed of data uploads to S3, which is governed by other factors such as network conditions and the user's