A Presigned URL, also known as a “pre-signed URL,” is a time-limited URL that provides temporary access to a specific resource or operation in a web application. In the context of Amazon S3 (Simple Storage Service), a Presigned URL allows users to grant time-limited, secure access to private objects stored in S3 buckets.
When generating a Presigned URL, the owner of the resource (typically an S3 object) includes a signature with the URL. This signature is generated using the owner’s AWS security credentials, such as access key and secret access key, and it verifies the authenticity and integrity of the URL. The Presigned URL also contains the necessary information about the desired operation, such as GET or PUT, and the expiration time for the URL.