Blockchain

I. Overview link

%%{init: { 'theme': 'base', 'themeVariables': { 'edgeLabelBackground': '#fff' }}}%%
flowchart LR
    A["Centralized\nSingle authority"] -- "Distributed consensus\nand chaining" --> B["Distributed ledger\nShared across participants"]
    style A fill:#f9f9f9,stroke:#333,stroke-width:3px
    style B fill:#e1f5fe,stroke:#01579b,stroke-width:3px

Definition: A distributed ledger technology in which every network participant shares and cross-checks the transaction ledger, guaranteeing the transparency and integrity of the data.

Features:
( Decentralization ) Transactions take place directly over a P2P network with no central administrator, eliminating any single point of failure ( No SPoF ) and ensuring availability.
( Integrity ) Block chaining via hash functions and the Merkle Root prevent data tampering and forgery.
( Visibility ) The ledger is open to every participant, maximizing the transparency and traceability of transactions.
( Irreversibility ) Once recorded, information cannot be modified or deleted without distributed consensus, giving it strong evidentiary value after the fact.

II. Mechanism & Components link

Block Structure and Chaining Mechanism link

flowchart LR
    subgraph B0["Block N-1"]
        direction TB
        H0["Header\nPrev Hash: 0000\nMerkle Root\nNonce"]
        D0["Body\nTransactions"]
    end

    subgraph B1["Block N"]
        direction TB
        H1["Header\nPrev Hash: Hash(N-1)\nMerkle Root\nNonce"]
        D1["Body\nTransactions"]
    end

    subgraph B2["Block N+1"]
        direction TB
        H2["Header\nPrev Hash: Hash(N)\nMerkle Root\nNonce"]
        D2["Body\nTransactions"]
    end

    B0 -->|"Hash link"| B1 -->|"Hash link"| B2

• Block Header: Contains the previous block’s hash (Previous Hash), the Merkle Root, and a Nonce, maintaining the linkage between blocks.
• Block Body: The set of actual transaction records.
• Merkle Root: Summarizes individual transactions as a hash tree, enabling fast verification of whether data has been tampered with.

Four Core Technologies of Blockchain Operation link

III. Comparison & Application link

A private chain run and validated by a single company is, for most practical trust purposes, just a distributed database with extra steps — the trust model only meaningfully changes once governance and validator rights are genuinely shared across parties with competing interests, which is what a consortium chain is actually for. Pick public only when participants must transact without trusting each other or any operator; pick private or consortium when participants already have a legal relationship and simply need a shared, tamper-evident record of it.