The Stellar Consensus Protocol (SCP) is a decentralized consensus mechanism designed to achieve agreement across a distributed network of computers, or nodes, without the need for a central authority. Developed by Professor David Mazières, SCP is the underlying consensus algorithm used by the Stellar network, which facilitates fast, reliable, and secure financial transactions.
Key features of the Stellar Consensus Protocol include:
- Federated Byzantine Agreement (FBA): SCP employs a Federated Byzantine Agreement system, which allows nodes to select which other nodes they trust. This creates a flexible and decentralized trust model, where consensus can be reached even if some nodes are unreliable or malicious.
- Quorum Slices: Each node in the network chooses its quorum slices, which are sets of nodes it trusts. A quorum is reached when there is an overlap of quorum slices among different nodes, ensuring that consensus is achieved without needing all nodes to agree.
- Safety and Liveness: SCP ensures both safety and liveness in the network. Safety means that nodes cannot reach conflicting decisions, and liveness ensures that the network continues to make progress even in the presence of node failures or network partitions.
- Asynchronous Operation: The protocol operates asynchronously, allowing nodes to reach consensus without requiring them to be online simultaneously. This makes SCP robust to network delays and partitions.
- Low Latency: SCP is designed to confirm transactions quickly, typically within a few seconds, making it suitable for high-speed applications like financial transactions.
Overall, the Stellar Consensus Protocol provides a secure and efficient way to achieve consensus in a decentralized environment, supporting the Stellar network’s goal of enabling fast and low-cost cross-border payments.