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Coder Spirit


I'm Andrés Correa Casablanca. I work as a software engineer, but I have a scientist in my heart. I love mathematics, algorithms, AI, and machine learning.


Introduction to the Blockchain (Cryptocurrencies)

So… I wanted to write this article since 6 weeks ago, when I started to delve into cryptocurrencies development, and today is the day :) .

Disclaimer: First and foremost, I’m not a blockchain and/or cryptocurrencies fanboy, neither a hater. I think the right way to approach this topic is through highly critical thinking, a lot of patience and will to learn.

There’s a lot of potential on this field, yet a lot of empty promises too, and to discern what’s serious from what’s not one needs to dig deep… and believe me, it’s a tough task. The field is deeper than one could imagine without having previous exposition: the number of open questions & open problems is high, and this is in part due to its interdisciplinary nature (cryptography, distributed systems, networking, software & networks security, economics…).

My aim here is not to write a tutorial, but to explain my own learning process, and in order to do that I’ll continue writing more articles to talk about very specific topics in almost self-contained texts.

Having said that, I’ll center my attention on the cryptocurrencies landscape rather than focusing on the more fuzzy “blockchain” term, because that’s what I’m working on, and that’s where my learning experience is mostly focused.

Let’s start then ☺. The story doesn’t really start with Bitcoin, but that will be our first stop because it’s where all the pieces where put together for the first time.

Knowing about the following concepts is a pre-condition to advance through the next steps without problems:

I truly recommend to read this two articles in order:

The first one introduces what’s nowadays commonly known as “Proof of Work”, and it was mainly designed to make spamming more difficult, using it for electronic currencies was a novel idea at the time (but introduced prior to the Bitcoin’s outbreak).

The second article is considered the foundational article of the blockchain & cryptocurrencies fields. It introduces the “Nakamoto consensus” idea (consensus between nodes achieved through “proof of work”) and the “blockchain” idea. It’s worth to say that the word “blockchain” is not used in that paper, Satoshi Nakamoto used “proof-of-work chain” instead.

The first Bitcoin implementation arrived some months after the article publication, and it was done applying other relatively new inventions that were not explicitly mentioned in the foundational article: smart contracts, an idea proposed by Nick Szabo in 1994 and extended in 1996.

I have to say that the “smart contracts” concept was for me one of the hardest points to understand when I started. I had previous knowledge about how the blocks were chained, about the proof of work… but not about that. And it’s easy to see why: it’s not mentioned at all in the Bitcoin paper, Nick Szabo’s didn’t give too many clues about how they should work, and it’s difficult to find good explanations about what they really are and how they work (most of what you’ll find in the Internet is pure bullshit, empty words).

One book where I found a pretty good explanation is “Mastering Bitcoin, 2nd Edition”, written by Andreas Antonopoulos. You can find an online and free version in Github: bitcoinbook/bitcoinbook, I truly recommend to read it if you’re just starting.

Notice: Might be the case that at this point you are surprised, could be that you read somewhere, or that somebody told you that the smart contracts were introduced in Ethereum… but that’s plainly wrong. Bitcoin also allows to implement smart contracts, and in fact it uses them all the time.

The key difference is on the capabilities that the scripts have in one platform or another. While in Bitcoin the scripting capabilities were limited on purpose to be non-Turing complete for security reasons, Vitalik Butterin proposed a way to securely execute smart contracts without limiting their capabilities (it’s worth to say that this came at a price, but I’ll leave this point for some future article).

Here I end my first and very brief post, but as a bonus I’ll link two interesting articles about who could be the mysterious Satoshi Nakamoto:

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