The irony is that such a scheme for publicly disclosing proof you have a piece of data without immediately publishing the data requires public key cryptography

The irony is that such a scheme for publicly disclosing proof you have a piece of data without immediately publishing the data requires public key cryptography and digital signatures to be public knowledge. [0] [0] https://en.wikipedia.org/wiki/Zero-knowledge_proof https://en.wikipedia.org/wiki/Zero-knowledge_proof