ssekmsKeyId

If x-amz-server-side-encryption has a valid value of aws:kms or aws:kms:dsse, this header specifies the ID (Key ID, Key ARN, or Key Alias) of the Key Management Service (KMS) symmetric encryption customer managed key that was used for the object. If you specify x-amz-server-side-encryption:aws:kms or x-amz-server-side-encryption:aws:kms:dsse, but do not providex-amz-server-side-encryption-aws-kms-key-id, Amazon S3 uses the Amazon Web Services managed key (aws/s3) to protect the data. If the KMS key does not exist in the same account that's issuing the command, you must use the full ARN and not just the ID.

This functionality is not supported for directory buckets.