A block is a unit of data that contains a group of transactions that are verified and added to a blockchain.
In blockchain technology, a block is a unit of data that contains a group of transactions. Each block is verified and added to the blockchain by a network of computers known as nodes. Blocks are added to the blockchain in chronological order, creating an immutable and transparent ledger of all transactions.
Blocks are typically created through a process known as mining, which involves solving complex mathematical equations to validate transactions and add them to the blockchain. Each block contains a unique cryptographic hash that links it to the previous block in the chain, creating a secure and tamper-proof record of all transactions.
Blocks can vary in size depending on the blockchain technology being used. For example, the Bitcoin blockchain currently has a block size limit of 1 MB, which can accommodate approximately 3-4 transactions per second. Other blockchains, such as Ethereum, have larger block sizes and can process more transactions per second.
Once a block is added to the blockchain, it cannot be altered or deleted without also modifying all subsequent blocks in the chain. This makes the blockchain an extremely secure and transparent method for recording transactions.
In addition to transactions, blocks can also contain other data such as smart contracts, which are self-executing contracts with the terms of the agreement between buyer and seller being directly written into code. These smart contracts can be used for a variety of applications, such as supply chain management, real estate transactions, and financial services.