Amazon S3 now supports five additional checksum algorithms: MD5, XXHash3, XXHash64, XXHash128, and SHA-512, bringing the total to ten. S3 validates and stores the checksum alongside your object for any of these supported algorithms, so you can verify data integrity end to end without additional tooling. When uploading objects, you can provide a checksum value and S3 validates it against the uploaded data before storing the object. For multipart uploads, you provide part-level checksums and S3 calculates a composite checksum upon completion. If you do not provide a checksum on upload, S3 automatically calculates and applies a CRC64NVME checksum as default integrity protection. Similarly, you can request the stored checksum when downloading to verify your data. The new algorithms work with S3 Replication, so you can replicate objects across buckets while preserving checksums, as well as S3 Inventory so you can audit checksums for datasets over time. For pre-existing objects that were uploaded without a checksum or with a different algorithm, you can use S3 Batch Operations to calculate checksums at scale without downloading or restoring data. The new checksum algorithms are available at no additional cost across 37 AWS Regions, including the AWS China and AWS GovCloud (US) Regions. You can get started using the AWS CLI or AWS SDKs. To learn more, visit the S3 User Guide .