// this is kept in present form to be compatible with S3 owner ID
	// requirements -
	//
	// ```
	//    The canonical user ID is the Amazon S3–only concept.
	//    It is 64-character obfuscated version of the account ID.
	// ```
	// http://docs.aws.amazon.com/AmazonS3/latest/dev/example-walkthroughs-managing-access-example4.html