Blockchain as a tool for providing Proof of Authenticity, Proof of Integrity and Proof of Authorship for digital and digitalized information
particularly attested documents and pieces of intellectual property
A blockchain is a distributed database that is used to maintain a continuously growing list of records, called blocks. Each block contains a timestamp and a link to a previous block. A blockchain is typically managed by a peer-to-peer network collectively adhering to a protocol for validating new blocks. By design, blockchains are inherently resistant to modification of the data. Once recorded, the data in any given block cannot be altered retroactively without the alteration of all subsequent blocks and the collusion of the network. Functionally, a blockchain can serve as “an open, distributed ledger that can record transactions between two parties efficiently and in a verifiable and permanent way. …”.
The poor man’s copyright method as a proof of authorship and proof of priority mechanism has existed for decades and there is no widespread trustless alternative. Similarly, in most cases, exchanging official paperwork both domestically and internationally still requires the creation of attested copies and the utilization of a courier service. Not to mention, it takes several days and the prerequisite of a trust relationship with and between a large number of involved parties. In the 21st century, there must be a better way…
- Signed file hashes on a blockchain
- Authorized party (document issuer / notary) has a public key (which is publicly associated with its authority) and a private key (on a smart card / biometric identity document)
- State issued biometric passports as a personal identification and signature tool [see German eID] (a PIN/fingerprint protected smart card containing an individual private key generated inside a secure element)
A blockchain transaction would contain
- the transaction sender’s public key
- the file hash
- a timestamp
- Proof of Authorship (+ Proof of Priority): file hash and timestamp
- Proof of Authenticity: document issuer / trusted verification party signed file hash as part of the signed transaction
- Proof of Integrity: file hash
Use case 1
- The responsible government body signs a transaction containing the hash of the digital version of Alice’s birth certificate, broadcasts it to the network and shares a digital version of the document with Alice.
- Alice loses her passport and requests a new one by providing the unaltered digital copy of her birth certificate through an official web platform
- The system automatically looks up the relevant blockchain transaction by the file’s hash value and initiates the issuance of a new identity document, provided that the signee’s public key is authorized to issue / verify this kind of document and that the transaction is older than the public key’s date of expiration
Use case 2
- Bob needs to submit his Canadian diploma, his passport and a proof of funds to complete his master’s application at a Dutch university. He is also required to provide a proof of language proficiency.
- The admission office can only accept original documents or attested copies. Bob is not willing to risk the documents getting lost and therefore decides to have attested copies made by a local notary.
- After Bob has explained his situation, the notary tells him about the possibility of attesting digital copies of his documents. Even though Bob’s university does not accept digitally attested documents, there is another option: thanks to an international agreement, Bob’s notary can send a digitally attested copy of all documents to a postal notary service in the Netherlands which, after verifying the digital attestations of the scans on Canada’s official blockchain, can print them, add a Dutch attestation to each one and send them to the university. Unfortunately, a Canadian notary cannot attest a language proficiency certificate which is in Dutch. Thankfully, Bob remembers that he had also received a digital version from the language school which already has an entry on the official blockchain of the Netherlands thereby enabling the Dutch notary service to attest a printed copy. Bob's university receives the documents within a day.