Block

A collection of transactions recorded on the blockchain.

A block in a blockchain is like a single page in a very special kind of book where all the pages are connected in a very secure way. Here’s how you can think of it:

  • Page of a Book – Imagine each block as a page in this book. On this page, you write down all the new things that have happened, like transactions if it’s a cryptocurrency blockchain like Bitcoin. Each page can hold a certain number of these events or transactions.
  • Data – Each block contains:
        • Transactions: These are like entries in your ledger. For Bitcoin, these are records of who sent money to whom.
        • Timestamp: This tells you when this page was written, similar to the date on a newspaper.
        • Previous Block’s Fingerprint: This is called a “hash.” Think of it as a unique fingerprint of the previous page. If you change anything on that previous page, the fingerprint changes, making it clear if someone tried to alter it.
  • Link to the Past: Each new block (page) starts with a reference to the fingerprint of the last block. This creates a chain, where each page is linked to the one before it. This link makes it very hard to change any information because altering one block changes all subsequent blocks.
  • Security and Verification: Before this page can be added to the book, everyone who has a copy of the book (the network of users) must agree that everything on this page is correct. This agreement process can involve solving complex puzzles, which is what miners do in Bitcoin’s network.
  • Immutable Record: Once a block is added to the blockchain and enough time has passed (or enough blocks have been added after it), it’s very hard to change. This makes the information on each block permanent and trustworthy.

In simple terms, a block is where new information is stored, securely linked to all the previous information, making the entire history very hard to tamper with. Each block adds another layer of security and history to the blockchain.