Supported data integrity checks

Data integrity checks automatically calculate checksums for upload and download operations and verify that the data received matches the expected checksum.

This feature is enabled by default to detect accidental data corruption in transit and ensure end-to-end data integrity for all object operations.

Checksums can be automatically applied to the request payloads of the following operations:

• Upload (PutObject, UploadPart)
• Download (GetObject)
• Delete (DeleteObjects): Both Content-MD5 and newer checksum algorithms are supported for delete payload validation.

When uploading or deleting objects, the S3 service calculates and includes a checksum in the request, then verifies the integrity of the server response.

When downloading, the client verifies that the checksum returned by the service matches the locally computed value.

When copying an object, the copied object inherits the checksum from the source only if the original object already contains one. This ensures consistency of integrity metadata while avoiding unnecessary checksum generation for objects that did not originally include a checksum.

For more information about checking object integrity, refer to the Amazon S3 documentation.