What is Blockchain?

What is Blockchain?

The blockchain is like a recorder's book. What is written on the blockchain is recorded and certified, and its integrity and availability are guaranteed. If this content is also encrypted, it guarantees confidentiality. This unique and unalterable registry is distributed in several network nodes where each block stores information about that block, valid transactions, and its relationship with the previous and next block.

Although its use is strongly associated with cryptocurrencies, this technology can be used for other types of digital assets, such as NFTs, contracts, etc. That said, the blockchain allows transactions to be recorded and an asset to be tracked within the network without intermediaries since the thousands or millions of nodes that make up the network (distributed teams) are the ones in charge of verifying and validating those transactions that take place. It will be recorded in a new block added to the chain.

In the case of cryptocurrencies, we can think of it as the accounting book where each transaction is recorded. Its operation can be complex to understand if we delve into the internal details of its implementation, but the basic idea is easy to follow.


There is some data in each block:

  • several valid records or transactions,
  • information regarding that block,
  • The link with the previous block and the next block through the hash of each block ─a unique code that would be like the block's fingerprint.

Therefore, each block has a specific and immovable place within the chain since each block contains information about the previous block's hash. The complete chain is stored in each node of the network that makes up the blockchain, so an exact copy of the chain is stored in all the participating nodes of the network.

As new records are created, they are first verified and validated by network nodes and then added to a new block linked to the chain.

Why is blockchain so secure?

Being a distributed technology, where each network node stores an exact copy of the chain, the availability of information is guaranteed at all times. If an attacker wants to cause a denial of service, he should disable all the nodes on the network since it is enough for at least one to be operational for the information to be available.

On the other hand, as it is a consensual registry, where all the nodes contain the same information, it is almost impossible to alter it, ensuring its integrity. If an attacker wanted to modify the information in the blockchain, he would have to adjust the entire chain in at least 51% of the nodes.

Blockchain technology allows us to store information that can never be lost, modified, or deleted.

Lastly, since each block is mathematically linked to the next block, it becomes unalterable once a new one is added to the chain. If a block is modified, its relationship with the chain is broken. In other words, all the information recorded in the blocks is immutable and perpetual.

Blockchain technology allows us to store information that can never be lost, modified, or deleted.

In addition, each node of the network uses certificates and digital signatures to verify the information and validate the transactions and data stored in the blockchain, ensuring the authenticity of said information.

In this way, we can think of blockchain as a scribe. A means to certify and validate any information. A reliable, decentralized registry, resistant to data manipulation, and where everything is recorded.

Today we are used to centralized models. We give all our information to companies like Google or Facebook to manage it; we send all our messages through the Telegram or WhatsApp servers to take care of sending them or spend fortunes on notaries and institutions so that they certify and keep our deeds or important documents.

In a blockchain, the data is distributed in all the network nodes. Since there is no central node, everyone participates equally, storing and validating all the information. It is a powerful tool to communicate and store information reliably, a decentralized model where the information is ours since we do not depend on a service company.

What other uses are given to blockchain?

Any information that should be preserved intact and remain available can be stored on the blockchain in a secure, decentralized, and cheaper way than through intermediaries. In addition, if this information is stored encrypted, its confidentiality can be guaranteed since only those who have the encryption key can access it.

Use of blockchain in health

For example, health records could be unified and stored on the blockchain. In this way, each patient's medical history would be safe and, at the same time, available to each authorized doctor, regardless of the health center where the patient was treated. Even the pharmaceutical industry can use this technology to verify drugs and prevent counterfeits.

Use of blockchain for documents

On the other hand, it would be very useful for managing digital goods and documents. So far, the problem with digital is that everything is easy to copy, but blockchain allows you to record purchases, deeds, documents, or any digital asset that cannot be forged.

Currently, there are already current projects that are worth investigating:

Hyper Ledger Project

It is a consortium of large companies looking to explore blockchain-based solutions. They have several active projects.

R3 Cev

In this case, the 40 largest banks in the world have come together to find solutions to their financial processes based on blockchain. In addition, they have reports and research on this technology.


The first blockchain-based storage initiative available to anyone. User data is encrypted and stored on the blockchain for preservation.

Proof of Existence

An online certification service for any type of document. It offers the possibility of saving a document in the blockchain, which can never be altered or deleted.

According to a survey by the consulting firm Deloitte, 74% of the companies consulted see blockchain as an improvement for the business and plan to invest in this technology. At the same time, almost half of these already have blockchain implementation in their business.

Without a doubt, blockchain makes the immutable and decentralized layer that the Internet has always dreamed of a reality. It is a technology that allows confidence to be removed from the equation and replaced with mathematical truth.