Abstract. Suppose an author has created a document that he wants to publish anonymously, but at some point in the future he would like to have the option to prove both his identity and the time of creation. A digital signature can be used to sign the document's content, but there is no mechanism to prevent another person from spoofing the timestamp and signing their own version of the document to claim they are the original author. Using a public, permanent blockchain such as bitcoin could allow the author to augment the digital signature with a timestamp that could be proven to match the document signature. The signature and timestamp could be stored privately until the author wishes to claim ownership at a later date. This might be compared to a privately-held NFT.
Will anyone ever prove the identity of [Satoshi Nakamoto](https