Hey, guys, I'm a fan of posts who try to clarify otherwise well-known and used terms in the spehre for the new people here (or the ones who just haven't met the terms before), so I'm making a similar one.

Introduction

In basic terms, a blockchain is a distributed digital database. Blocks of data are organized in chronological order. The blocks are linked and secured by cryptographic proofs. The implementation of this technology across different industries is already changing how we work and live.

The idea is that decentralized and secure blockchains allow for a world where we don’t need to rely on third parties for networks or markets to function. However, experts generally agree that if this tech is to be more widely adopted there’s a core problem that needs solving. The problem in question is known as the “blockchain trilemma”.

This term was popularized by Ethereum co-founder Vitalik Buterin. For it to make sense, you need to be aware of three different elements that are desirable in a blockchain: decentralization, security, and scalability. The blockchain trilemma refers to the idea that it’s hard for blockchains to achieve optimal levels of all three properties simultaneously. Increasing one usually leads to a weakening of another.

The Three Fighting Factors

You know how you can’t balance a social life, work, and sleep easily? The blockchain trilemma is similar. It’s the belief held across the cryptocurrency community that truly decentralized networks need to choose between security and scalability. Let’s have a quick look at them before we dive in.

What is Decentralization?

Decentralization talks about how control is shifted from one central entity, company, or government and is split across smaller groups to govern something. In blockchain, decentralization gives power to people across the world to govern using their computer rather than having a central control of the network live with one person or party.

What is Security On The Blockchain?

Blockchain is inherently secure, but is not entirely immune to hacking. If a hacker is able to secure control of more than half of the network (51%), they are able to alter a blockchain and manipulate transactions to steal from the network. In blockchain, the more nodes, the more security.

What is Scalability?

Scalability in blockchain is the same as in business – it refers to how much a network can grow in the future while maintaining the same sort of transaction speed and output.

Scalability and decentralization tag-teaming up tends to compromise security, while security restricts changes that allow the decentralized network to scale. Why? Well, basically because decentralized networks take a bit of work to operate and it makes scaling a little difficult.

But Why Do Blockchains Need To Scale?

You know how awful it is to sit in traffic? Traffic on a road exists because roads weren’t built to scale the number of cars that would be on the road at the same time. Imagine every time you had to make a transaction, you had to wait in traffic for your transaction to be validated and go through. And more people transacting means the more the network and validation process needs to happen. It creates traffic on an unscalable network, presenting an unsustainably slow approach.

So simply put, if blockchain technology is going to reach any sort of mass adoption, scalability is critical. If a network can’t scale, it just won’t be able to compete with traditional platforms in convenience, transaction speed, and throughput.

Although most people might not know about the blockchain trilemma, there is an awareness of the problems it presents (like Bitcoin’s slower transaction speed). If projects are able to successfully solve the trilemma, we could be looking at new levels of blockchain adoption.

TL;DR

Blockchains can only handle a limited number of transactions per second. The Bitcoin network, for example, can process around seven transactions per second. If blockchain technology is to be adopted globally, it should be able to handle much more data, and at faster speeds, so that more people can use the network without it becoming too slow or expensive to use. However, the fundamental design of many decentralized networks means that increasing scalability tends to weaken decentralization or security. This is what’s known as the blockchain trilemma. Developers looking to solve this problem are experimenting with different consensus mechanisms and scalability solutions, such as sharding, sidechains, and state channels.

The information above is taken from the following two articles, go there for details, the techs trying to offer a solution, and to give some clicks to the original authors:

https://academy.binance.com/en/articles/what-is-the-blockchain-trilemma#Introduction

https://www.ledger.com/academy/what-is-the-blockchain-trilemma

​