Long before the Internet was created, proving that you created something required either a laborious and expensive legal application or a variety of other dubious strategies such as the poor man's copyright of posting documents to yourself. Just as much else has drastically changed with the emergence of new technologies, so has proving your ownership of such works.
Why should any of this be important? Let us suppose that a for-profit online magazine takes one of your non-commercial Creative Commons licensed blog posts and puts it on their website. How would you prove that you were the original author? The date listed on the post? Easily forgeable. The modification date of the document on your PC? Easily faked. That GPG signature for everything you wrote? Proves nothing about the date. Unless you happen to be paranoid or crazy enough to file a copyright claim for every piece of writing, there has never been a simple or easy answer...until now.
The advent of decentralised crypto-currencies introduced the concept of the blockchain -- a public distributed database that maintains a continuously growing list of records, called blocks, secured from tampering and revision. This allowed for a clear record of all financial transactions, but soon people began to see the value of this principle in other arenas. In 2015, a research paper titled Decentralized Trusted Timestamping using the Crypto Currency Bitcoin was published on arXiv. Its summary gave a clear indication of what the blockchain principle could do for proof of origin:
Trusted timestamping is a process for proving that certain information existed at a given point in time. This paper presents a trusted timestamping concept and its implementation in form of a web-based service that uses the decentralized Bitcoin block chain to store anonymous, tamper-proof timestamps for digital content. The service allows users to hash files, such as text, photos or videos, and store the created hashes in the Bitcoin block chain. Users can then retrieve and verify the timestamps that have been committed to the block chain. The non-commercial service enables anyone, e.g., researchers, authors, journalists, students, or artists, to prove that they were in possession of certain information at a given point in time. Common use cases include proving that a contract has been signed, a photo taken, a video recorded, or a task completed prior to a certain date. All procedures maintain complete privacy of the user's data.
The researchers created OriginStamp.org, a free and anonymous web-based platform that enables you to prove that you were the original source for a given piece of information. The system automatically creates a trusted and verifiable timestamp stored in the Bitcoin blockchain.
Proofofexistence.com is yet another free service that uses the same blockchain principle for any document. As they make clear:
The key advantages are anonymity, privacy, and getting a decentralized proof which can't be erased or modified by anyone (third parties or governments). Your document's existence is permanently validated by the blockchain even if this site is compromised or down, so you don't depend or need to trust any central authority. All previous data timestamping solutions lack this freedom.
It takes little imagination to grasp the immense implications for such near-effortless certification. Indeed, there may come a time when the same blockchain principle is embedded within applications, so that an email, a saved document or a published web page is immediately registered on a decentralised blockchain ledger. There are a whole host of reasons why individuals and organisations would choose to to use the blockchain in this way. Who created what and when is often of key importance in every society, but equally significant is that it presents yet another step towards a re-decentralised Web.