Generic Elements of a Blockchain:
The structure of a generic blockchain consists of the following core elements. These elements are common across most blockchain platforms and define how blockchain works:
1. Address:
- An address is a unique identifier in the blockchain used to identify participants.
- It is used to denote the sender and recipient in a transaction.
- Technically, an address is usually a public key or is derived from a public key using cryptographic hashing.
2. Transaction:
- A transaction is the basic unit of a blockchain.
- It represents a transfer of value from one address to another.
- Transactions are recorded in blocks and are cryptographically signed to ensure integrity and authenticity.
3. Block:
- A block is a container of transactions.
- It consists of two parts:
- Block Header
- Block Body (contains the list of transactions)
Block Components:
a. Previous Block Hash:
- Each block contains a reference to the previous block (except the genesis block).
- This reference is stored as the hash of the previous block’s header.
- It ensures linking between blocks to form a chain (hence, “blockchain”).
b. Genesis Block:
- It is the first block of the blockchain.
- Hardcoded at the time the blockchain is launched.
- It does not reference any previous block.
c. Nonce:
- A nonce is a number used only once.
- Used in Proof-of-Work (PoW) and for replay protection.
- It ensures that mining a block requires effort, providing security.
d. Timestamp:
- Represents the creation time of the block.
- Used to order transactions and blocks over time.
e. Merkle Root:
- A single hash representing all transactions in the block.
- Built using a Merkle Tree, which is a binary tree of hashes.
- Merkle Root ensures efficient verification of all transactions in a block.
- Verifying the Merkle root is enough to verify the integrity of all transactions.
