A blockchain is a distributed, decentralized ledger that securely stores data in blocks. Each block contains a set of transactions or data and is cryptographically linked to the previous one.
These links are formed using a cryptographic hash function known as SHA-256, which converts data into a fixed-size string of characters, often represented in hexadecimal (0-9, A-F). This process is irreversible, meaning the original data cannot be retrieved from the hash.
The SHA-256 hash function exhibits an avalanche effect: even a small change in the input data results in a completely different output hash. This makes blockchain highly secure, as any attempt to alter a block's data would change its hash, invalidating the entire chain.
Each block in the chain contains a reference to the previous block’s hash, forming a secure, tamper-evident chain.
The Genesis Block, or the first block in the blockchain, is unique as it has no previous block to reference. However, every subsequent block is linked to its predecessor by referencing its hash, creating a permanent and immutable chain of blocks. This method of linking blocks ensures data integrity and allows for transparent, secure monitoring of the blockchain’s health.
The Genesis Block is the first block in the blockchain. It is the foundation of the entire chain, and it does not reference any previous block since it is the very first one. Its unique identifier is 1, and it has no previous block.
Block 2 has a unique identifier of 2. It references the Genesis Block, meaning it acknowledges the first block in the chain as its predecessor. This is what links all blocks together in the blockchain.
This is the Genesis Block. Its unique identifier is 1. It has no previous block.
This is Block 2. Its unique identifier is 2 and the previous block's ID is 1.
This is Block 3. Its unique identifier is 3 and the previous block's ID is 2.
This is Block 4. Its unique identifier is 4 and the previous block's ID is 3.
This is Block 5. Its unique identifier is 5 and the previous block's ID is 4.
This is Block 6. Its unique identifier is 6 and the previous block's ID is 5.
This is Block 7. Its unique identifier is 7 and the previous block's ID is 6.
This is Block 8. Its unique identifier is 8 and the previous block's ID is 7.
This is Block 9. Its unique identifier is 9 and the previous block's ID is 8.