Blockchain in Payments
Working principles, network types, consensus mechanisms, DeFi protocols, stablecoins, and CBDCs — a technical guide to blockchain technology and its integration with modern payment infrastructure.
What is Blockchain?
A blockchain is a distributed, append-only ledger maintained by a network of nodes with no central authority. Records are grouped into blocks, each cryptographically linked to the previous one via a hash pointer — forming a chain. Altering any historical record invalidates every subsequent block, making the ledger tamper-evident. In payments, blockchain enables value transfer, settlement, and programmable money without trusted intermediaries.
Decentralised
No single operator controls the network. Thousands of independent nodes each hold a full copy of the ledger and validate transactions independently using shared consensus rules.
Immutable
Once a block is buried under enough subsequent blocks, rewriting it requires re-mining every block that follows — computationally infeasible on large PoW networks. History cannot be quietly altered.
Transparent
All transactions on public blockchains are visible to anyone. Addresses pseudonymous, not anonymous. On-chain analytics can trace fund flows, supporting compliance and dispute resolution.
Programmable
Smart contract platforms (Ethereum, Solana) allow arbitrary logic to run on-chain: conditional payments, escrow, token issuance, lending rules — executed identically by every node in the network.
Traditional Database vs. DLT vs. Public Blockchain
| Property | Traditional DB | Permissioned DLT | Public Blockchain |
|---|---|---|---|
| Control | Central operator | Known consortium | No single party |
| Write access | Authorised users | Authorised nodes | Anyone (with fees) |
| Trust model | Operator trust | Consortium trust | Cryptographic / economic |
| Finality | Immediate (DB) | Fast (seconds) | Probabilistic or economic |
| Throughput | Very high | High (1K–10K TPS) | Low–medium (7–65K TPS) |
| Privacy | Full control | Configurable | Pseudonymous / public |
| Auditability | Operator-controlled | Members only | Universal, permissionless |
| Payment example | SWIFT, Visa core | JPM Onyx, R3 Corda | Bitcoin, Ethereum, XRPL |