Sharing data between different entities


#1

Let’s assume I am a User who has a blockstack ID . I want to share certain documents (subset A) with Party A. Party A verifies my documents and provides me with a DocumentB. Suppose I want to prove to another party, PartyB that my documentB exists on chain, What would be the underlying procedure.

From what I have read , I am assuming that a each time a file get’s added to my local db, zone hash remain’s same but data is added. I don’t seem to understand this concept. How can data change be monitored ?

Please excuse me if my understanding is incorrect. If it is so , do let me know what the process would actually be.

Regards,
Sandra


#2

Party A has the ability to store the document hash and signature to a zone file, and then it will be anchored to the blockchain at a particular block height and replicated to the entire Blockstack peer network. Party B will be able to confirm that party A signed the document (and proved that it existed) at a particular time. @nicktee’s Blockusign dapp does this today, for example.


#3

Hi @sandra

Yeah Jude is correct. Blockusign uses a combination of blockstack technologies to achieve this. This forum post explains it in detail How to sign data with app private key . This github issue discusses some of the technical details https://github.com/ntheile/blockusign/issues/58