What is a block?

A block, or block in French, is a part of the blockchain (block chain) that is issued at regular intervals in order to record the transactions that have been carried out via a given cryptocurrency.

In other words, it is the main element that makes it possible to guarantee the integrity of the operations that have been carried out on digital assets (at least those operating with a blockchain) and the immutability of the latter.

How many blocks can a blockchain contain?

The number of blocks that a blockchain can contain is in principle unlimited. Indeed, as long as the considered digital currency is active, it must necessarily continue to produce new blocks in order to allow its users to carry out transactions on its network.

As a result, the older a cryptocurrency is, the larger the size of its blockchain becomes because all previous transactions are engraved on it permanently in most cases.

What is block numbering for?

The blocks are usually numbered because this makes several things easier. First of all, we can refer to the number of a block to indicate that such a transaction has been carried out at this precise moment. This makes it easier to find the operations carried out.

Then it is possible for a special event to occur at a given block. For example, the source code of Bitcoin indicates that a halving takes place every 210,000 blocks, thus mechanically reducing the rewards awarded to miners.

For some cryptocurrencies, such asEthereum, you can also decide that an update must take place once you reach a specific block number. In this case, nothing is decided in advance in the code base, but is implemented by the programmers according to the wishes of the community. In the case of some digital assets, the number of the block where the update must take place is decided by a vote.

Can a block registered in the blockchain be deleted?

The concept of the blockchain is the immutability of transactions, that is, it is not possible to go back when something has been approved by miners. Generally, when a block is approved, it is no longer possible to remove it from the blockchain.

However, the blockchain may temporarily split between several different blockchains, until one of them is considered “official” by miners. In this case, the “unofficial” string disappears.

It has also happened that certain transactions were deleted when a hacking attempt was successful. We can cite the example of Ethereum which decided to return a few blocks before the hack of The DAO considering that all transactions carried out after this event were no longer valid, which resulted in a fork between Ethereum (ETH) that we currently know and the Ethereum Classic (ETC) whose members refused to go back because the immutability of transactions had to be the rule for them, even in the event of a hack.

Conclusion on the block

The block is an element that allows you to record a group of transactions that have been carried out on a given digital asset. The size of the latter, i.e. the number of transactions it can contain, and its duration, i.e. the time required before a new block is created, depends on each cryptocurrency. .

The block is the basic element that makes the blockchain work, which as its name suggests, consists of a chain of blocks placed end to end.

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I discovered the world of cryptocurrencies in January 2018. Arrived at the worst time to invest, I have never stopped training since then and now share my knowledge in order to facilitate the adoption of cryptos.

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What is a block?

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