relies only on the sequences of bytes that make up a digital object, without reference to any structures within the data stream, or to any meaning the byte stream may have when appropriately interpreted. Such methods have the widest applicability as they can be applied to any piece of data; however, they also carry the implicit assumption that artifacts that humans perceive as similar have similar byte-level encodings. This assumption is not universally valid. Analyst expertise is necessary to evaluate the significance of a byte-level match.
NIST SP 800-168