It's been quite a journey! Writing for Medium and actually, get people to read what you write… it’s not easy at the beginning. However, just like for almost anything else, consistency is the key!

Now, after writing my 50th article, I start to collect the crops that I’ve planted months ago. The audience is growing, the number of followers is growing and the number of publications sending me messages to publish with them is also growing.

I’ve decided to do zero promotion of my articles because… let’s be honest, I don’t have a huge social media following and basically, if…


Cryptography Series II — Why are prime numbers extremely important in hashing and cryptography?

For hashing, prime numbers are used since they provide a better chance of creating unique values for a hash function. Hash functions (if you don’t know what hashing is please read this article) use modulus, and the use of composite numbers (i.e. non-prime) increases the probability of hash collisions (i.e. different inputs to result in the same hash). Prime numbers will increase the chance of creating unique values when hashing by multiplying values by the prime number. This is just the nature of mathematics. For example, if you have a string “Unblockchain”, multiplying each letter with a prime number and…


Cryptography Series I — Why are random numbers so, so, SO important?

Random numbers are probably the single most important thing in the world of cryptography. Without random numbers, cybersecurity couldn’t exist. Random numbers are the pillar of internet security and what allows us to transact securely on the internet. Every time we visit an HTTS website, we use random numbers. The S at the end of HTTPS stands for “Secure”, and it means the website’s data is encrypted at transit with TLS — Transport Layer Security — formerly known as SSL — Secure Sockets Layer. AND random numbers also help us to create Bitcoin addresses.

SSL uses an RNG — Random…


Cryptography Series III — how to manually generate an RSA key pair?

I’m sure you have heard of RSA. If you haven’t heard, I can tell you that you have already used RSA on your computer today! What is this RSA thing about? Digital signatures! RSA encryption is pretty much used everywhere, including in Bitcoin and most blockchains!

In the previous two articles of this cryptography series, I have talked about:

If you want to learn more about what makes a strong private key, please also read those articles!

RSA is used…


And also the block’s difficulty!

What’s behind all those fields in the Bitcoin block? You probably have already used a block explorer to check the status of a transaction or check wallet transactions or balance (yes, everything is super transparent in the blockchain), but what are all those fields and long numbers, right?

You don’t really need to know what are all those fields and long numbers. Just like an email user doesn't need to know how the internet and email protocols work from the technology perspective, a blockchain or Bitcoin user doesn’t really need to know how does it work to send a transaction…


In any blockchain, there’s an ongoing war between good and evil! Good nodes want to keep the true state of the blockchain but bad actors want to make fraudulent transactions! Solving the Byzantine General’s Problem allows us to win the fight against evil nodes and even tolerate them!

This article is part of a series of articles where I talk about other consensus mechanisms. You can check the links below after you finish reading about PBFT ⚔

Let’s go to war!

Nodes in the blockchain are like generals and soldiers in a war

A blockchain is like a constant war between good nodes and evil nodes. Being a distributed network with dozens, hundreds or sometimes thousands of nodes need to agree on…


Proof of burn (POB) is a consensus algorithm that tries to address the high energy consumption issue of a Proof of Work — Bitcoin’s consensus. Does this proof of burn work?

“Burnt coins are mining rigs!”

Iain Stewart

Let’s start burning stuff!

There’s many consensus mechanisms that I will be covering in a series of articles. You can check some of them in the links below:

So… do we just burn the coins?

Invented by Iain Stewart, Proof of burn is an experimental consensus mechanism and a fascinating concept: Slimcoin, a defunct cryptocurrency used to use it. …


Should we have democracy in blockchains? Do we trust DPoS blockchains?

“Democracy is the worst form of government, except for all the others.”

Winston S. Churchill

There’s a number of consensus mechanisms that I will be covering in a series of articles. You can check some of them in the links below:

What is a Consensus Mechanism

A consensus mechanism allows distributed systems and blockchains to work together…


What is Proof of Importance, how does it work, and why does it matter!

There’s a number of consensus mechanisms that I will be covering in a series of articles. You can check some of them in the links below:

So…. What is Proof of Importance Consensus?

A consensus mechanism allows distributed systems and blockchains to work together and stay secure. …


Just follow this step-by-step to be an Ethereum millionaire (on the test net)

This step-by-step was part of one of my NFT sessions where I was showing my students how to mint an NFT.

If you want to learn how to create NFTs. check out my NFT course on Udemy. If you are looking to grab some test Ether, just follow the steps!

Why would I want to have “test” Ether?

Well, there are different reasons why you may want to use some test Ether. Maybe you want to test how to create an NFT without incurring gas fees (the fees that you pay in the Ethereum network). Maybe you want to test a new Ethereum application that you have developed…

Henrique Centieiro

Passionate about Fintech, Blockchain, Agile Scrum and doges. https://www.udemy.com/user/henrique-246/ https://www.linkedin.com/in/henriquecentieiro/

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