Block

A block is a single unit from the entire blockchain that stores and encrypts data or information about a particular transaction. It is then linked to the previous and the next block, thus forming a chain. It’s a permanent record of information that cannot be altered.

Discover below a few characteristics of blocks:

• Security: Blocks are a secure way to store information through cryptographic hashing. Each block contains a unique digital signature (hash) that is generated based on the contents of the block and the hash of the previous block. This interdependence makes it extremely difficult for malicious actors to modify block data without altering the entire chain. Indeed, changing one block's data would require recalculating the hashes for all subsequent blocks.
• Transparency: Anyone can access the transactions that are stored in blocks with a block explorer. This transparency ensures that all network participants have access to the same set of data, trust and accountability.
• Immutability: Once a block is added to the blockchain, it becomes extremely challenging to modify or delete the data within it. This immutability is crucial in blockchain technology.‍
• Decentralisation: Blocks are created and validated by a network of computers distributed across the blockchain. By being decentralised, blockchains eliminate the need for a trusted third party acting as a central authority, reducing the risk of single points of failure and enhancing security.

Blocks in blockchain contain several pieces of information about cryptocurrency transactions, including:

• Transaction data: Blocks store data about various transactions. In the context of cryptocurrencies like Bitcoin, these transactions represent the transfer of digital assets from one user to another. For other blockchain applications, transactions can include a wide range of data, such as ownership records, smart contract executions, or supply chain events.
• Timestamp: Each block includes a timestamp indicating when the block was created or mined. It’s crucial for establishing the order of transactions and ensuring that they cannot be modified retroactively.
• Hash: Each block contains a hash (a reference to the previous block in the chain) that helps maintain the chronological order of transactions. It ensures the integrity and immutability of the entire blockchain. Indeed, any change to a single block would require changing all subsequent blocks, which wouldn’t be technically possible due to the decentralised nature of the network.