“Hashing” a document has been a lynch pin of document security for most of the digital age. It uses an algorithm to create a unique identifier for a digital document. Useful for things like computer security and ediscovery. Perhaps time has moved on.
“Google Team Cracks Web Security Shield,” The Wall Street Journal, February 24, 2017 B4. The SHA-1 algorithm was cracked, allowing the creation of two different documents with the same hash value.
Alternatives in the works. Watch this space.