If you've ever heard about "Bitcoin", there's a big chance that you've also encountered the term "blockchain." However, did you know that this concept has been around since 1991?

"Wait, so you mean blockchain came first before Bitcoin?" 

Well, the birth of blockchain technology is generally regarded in 2008, when the pseudonymous author called Satoshi Nakamoto released a whitepaper entitled Bitcoin: A Peer to Peer Electronic Cash System. However, Satoshi's invention is actually built on earlier works. Some of which are Ralph Merkle's Ph.D. thesis called "tree authentication" and David Chaum's vault system. 

While there are numerous studies that explain different technologies on where the blockchain is based, there is one ground-breaking advancement in peer-to-peer computing that influenced the development of Bitcoin. In fact, even Satoshi Nakamoto cited the inventors three times in Bitcoin's whitepaper.

W. Scott Stornetta and Stuart Haber's timestamping (1991)

Before you get to know about timestamping, who are Stornetta and Haber? 

Dr. W. Scott Stornetta is a renowned scientist with a Ph.D in Physics, who spent more than 15 years in the field of research and tech corporations such as Xerox.

On the other hand, Dr. Stuart Haber is a cryptographer, holding M.Phil. and Ph.D. in computer science. He used to work for Bell Labs as a research scientist.   

So, how did everything start?

Everything started when Stornetta witnessed a manipulated research study by a prominent researcher in biology. When the examination of lab notebooks was conducted, the original results were discovered to have been altered with a different ink from the one used in other lab notebooks.

Furthermore, Xerox, the company where he used to work, also told him that in the future, all records will be digital. Since then, he knew that this is a big issue as digital records are easier to modify. This then sparked his idea of solving the problem of data alteration.

Xerox worked closely with Bell Labs during that time. From this, Stornetta met a cryptographer named Stuart Haber and convinced him to work on the aforementioned problem. 

Now, the solution they came up with was to use hash functions and digital certificates on documents and save them with a timestamp. 

But wait, what is a "hash"?

Hash is a widely used concept in cryptography that represents certain data.

Here's a quick example of a hash:

Let's say you live in a world where all of your actions are recorded. One day, you felt hungry and decided to buy a cheeseburger for ₱150. Your transaction will then generate a unique ID transaction, which cannot be duplicated or reversed. If you do another transaction, it will generate a new unique ID.

These unique IDs can be called as a "hash." In the context of Stornetta and Haber's solution, they wanted to use hashes for documents. In other words, each document, even with the smallest changes, will have its own unique hashes.

So, what is the connection of hash with timestamps?

Despite having a hash that represents a certain document that's irreversible, it can still be prone to fraud by altering the dates of electronic documents. Therefore, Stornetta and Haber's solution is to store hash values with a timestamp. By doing this, one can prove that a document with a specific version existed at a certain time. 

Okay, so how is this a chain?

In the paper they published, they described the time sequence as "linking." This means that documents are linked up in a structure by incorporating hashes of prior records' certificates. 

Similar to how a cryptocurrency blockchain works, each hash stored in blocks is tied to another hash, calling it a "blockchain."

So, did Satoshi Nakamoto just steal the idea of an existing work?

No, for 2 main reasons. 

First, he cited Haber and Stornetta three times in the whitepaper of Bitcoin.

Second, there may be no conceptual differences, but Satoshi Nakamoto added incentive layers such as the "proof-of-work consensus mechanism." Hence, it's not a complete duplicate of the original work.

Sure, Stornetta and Haber deserve more recognition and Satoshi is not the original creator of blockchain. But at the end of the day, one cannot deny Satoshi Nakamoto's brilliant execution of Bitcoin and how he sparked a movement that has disrupted the status quo of finance. Ultimately, what's bad in building on existing knowledge? If it's for the betterment of mankind, why not?