Blockchain: The *not* published database — Part I
While Cryptography is an integral part of blockchain which allows us to encrypt data and prove that data was signed by a known sender of the transaction on the other hand blockchain, bring truthfulness of data by confirming whether the piece of data was published or not called *Proof-of-Existence* consensus OR certain event happened or not called *Proof-of-Life* consensus.
*Proof of Existence*
Let’s analyse a real-world application of Proof-of-Existence
In this application, we store only the hash of the file into the bitcoin blockchain.
Let us understand how it does it evolve to a Proof-of-Existence consensus.
Firstly, hash of any data is always unique i.e. if *H(a) == *H(b) then we can conclude that a == b and if *H(a) != *H(b) then a != b. The important part to note is hashing cannot be predicted by any intellectual algorithm or logic, hence puzzle friendly.
*H(a) — hash of a
*H(b) — hash of b
Secondly, the storing of hash is nothing but a transaction to the bitcoin blockchain signed digitally by the sender’s private key. By digitally signing the receiver of the signed message or perhaps all the miners or transaction verifiers in the bitcoin network get the following information about the transaction:
1. Authenticity — The sender of the transaction/message was known (not personally, only his address was known)
2. Non-repudiation — The sender cannot deny sending the transaction/message
3. Integrity — The signed transaction/message was not altered during the transit.
thirdly, by storing such a digitally signed hash at a particular time into an open, decentralized, immutable ledger in which transactions are purely controlled by consensus of pseudonymous participants, and thus all the data in it is called a single source of truth that means anything published at a particular time was never changed.
Therefore we can conclude that a particular piece of data was published or not.
Okay… that’s fine but, how do I use it and where will it help me? 🤔
To store the hash of any data, it cost you 0.00025 BTC that is approximately 2.5 USD/10 MYR, which is cheaper than your Starbucks coffee. So with 10 MYR, you can store (with timestamp) photos (if you want to self copyright them, check out https://photochain.io/), pieces of evidence, witnesses, confessions, proof documents and even intellectual property agreements. Obviously storing in PDF files will be better. Later it can be brought up to prove certain data existed/published at a certain time and to resolve disputes in court trials, cases, etc. (depends if the country’s court accepts it as a valid document).
In the next part, we will discover about Proof-of-Life and see how certain famous individuals proved themselves to be alive when rumours about their death/assassination were prevalent. You can also use it to prove yourself alive…😂
Till then… See Ya!
