How Blockchain Ensures Immutability

Decentralized and Distributed Ledger

At its core, blockchain is a decentralized and distributed ledger. This means that instead of relying on a single central authority, the data is stored across multiple computers (nodes) in a network. Each node holds a complete copy of the blockchain, creating a redundant and secure system.

Cryptographic Hashing

Every transaction on the blockchain is grouped into a block. Each block is assigned a unique identifier, known as a hash, generated through a cryptographic function. This hash is derived from the previous block's hash and the data within the current block. Any alteration to the data in a block will result in a completely different hash, making it easily detectable.

Chain of Blocks

As new blocks are added to the blockchain, they are linked together in a chronological order. Each block contains the hash of the previous block, creating a chain of blocks. This chain ensures the integrity of the blockchain, as any modification to a previous block would invalidate the hashes of all subsequent blocks.

Consensus Mechanism

Blockchain networks utilize consensus mechanisms to ensure that all nodes agree on the same version of the blockchain. This process involves verifying transactions and adding new blocks to the chain. Popular consensus mechanisms include Proof-of-Work (PoW) and Proof-of-Stake (PoS).

Immutability and Security

The combination of these factors makes blockchain inherently immutable. Any attempt to alter the blockchain would require compromising a significant majority of nodes in the network, which is extremely difficult due to the decentralized and distributed nature of the system. This makes it highly secure and resistant to fraud, manipulation, and data tampering.

Summary

Blockchain's immutability stems from its decentralized and distributed ledger architecture, cryptographic hashing, chain of blocks, and consensus mechanism. These elements work together to create a tamper-proof system where every transaction is recorded and verifiable, providing a high level of security and trust.