Blockchain is a decentralized and distributed digital ledger technology that records transactions across many computers in a way that ensures the data can only be updated by consensus between participants in the system, and once entered, information can never be erased.

Key Principles of Blockchain

  1. Decentralization:
    • Traditional databases, like a SQL database, are centralized. In contrast, on the blockchain, every participant (nodes/computers) on the network has access to the entire database and the complete history of all transactions. This means the control and verification of data are decentralized.
  2. Transparency:
    • Changes to the public blockchain are publicly viewable by all parties, ensuring full transparency in the ecosystem. For privacy reasons, individual data or transaction details are encrypted and can only be viewed by individuals with a decryption key.
  3. Immutability:
    • Once a transaction is added to the blockchain, it cannot be changed or deleted. This feature ensures that no participant can alter past transactions.
  4. Consensus Algorithms:
    • This is a technique used to achieve agreement on a single data value among distributed systems or processes. Common consensus algorithms in blockchain include Proof of Work (PoW) and Proof of Stake (PoS).
  5. Security:
    • Transactions must be confirmed by the network using consensus models. Once confirmed, the transaction is encrypted and linked to the previous transaction, bolstered by the principles of cryptography.
  6. Smart Contracts:
    • These are self-executing contracts where the terms of agreement or conditions are written into lines of code. They automatically enforce and execute when trigger conditions are met.
  7. Pseudonymity:
    • Every transaction on a blockchain is tied to a unique alpha-numeric address, not directly linked to the participants’ personal identity. This ensures semi-anonymity in transactions.
  8. Divisibility:
    • In the context of cryptocurrencies built on blockchains, units can be divided into smaller sub-units, allowing for microtransactions.

Blockchain Types

  1. Public Blockchains:
    • Open to anyone, participants can join and participate in the network, validate and verify transactions, and create new blocks. Examples: Bitcoin, Ethereum.
  2. Private Blockchains:
    • Restricted to specific participants with permissions. They offer more control over who can join the network and submit transactions. Common in business settings. Example: Hyperledger projects.
  3. Consortium Blockchains:
    • Controlled by a consortium of members rather than a single entity or open to everyone. They strike a balance between decentralization and efficiency. Example: R3’s Corda.


  • Transparency: Enhanced traceability and transparency in transactions.
  • Reduced Costs: Minimizes intermediaries, leading to cost savings.
  • Enhanced Security: Cryptographic principles make blockchains secure against malicious attacks.
  • Trustless Environment: Transactions can occur between strangers without the need for central authority or trust.


  • Scalability: High energy consumption and slower transaction speeds, especially in Proof of Work systems.
  • Irreversibility: If mistakes occur, they cannot be reversed, which might lead to loss.
  • Storage: Every node in the network stores the entire blockchain, leading to significant storage requirements.


Blockchain’s decentralized nature offers transformative potential across industries, from finance to supply chain, healthcare, and beyond. By providing a secure, transparent, and immutable method of recording data, blockchain holds promise for reshaping the way transactions are conducted and verified in the digital age.