Blockchain immutability refers to the characteristic of a blockchain ledger that ensures recorded data cannot be altered, deleted, or tampered with. This property is fundamental to maintaining the integrity and trustworthiness of blockchain systems. Here’s how immutability is achieved and why it matters:
Cryptographic Hashing:
Each block in a blockchain contains a cryptographic hash of its data and the previous block's hash. This creates a unique digital fingerprint for each block. Any change in a block's data alters its hash, making tampering immediately detectable.
Linked Blocks:
Blocks are linked in a chronological chain. Each block references the hash of the previous block, forming a sequence that is difficult to alter. Modifying one block requires changing all subsequent blocks, which is computationally infeasible.
Consensus Mechanisms:
Blockchain networks use consensus algorithms like Proof of Work (PoW) and Proof of Stake (PoS) to validate new blocks. Altering a block would require gaining control of the network’s consensus mechanism, which is prohibitively expensive and complex.
Decentralization:
The blockchain is maintained across a distributed network of nodes. Each node has a copy of the entire blockchain and continuously verifies the integrity of the ledger. This decentralized structure prevents any single entity from making unauthorized changes.
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