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Proof of Federation (hierachain/consensus/proof_of_federation.py)

Overview

Proof of Federation (PoF) is a consensus protocol designed specifically for Consortium networks, where multiple organizations (banks, hospitals, supply chain partners) jointly govern without any single entity holding absolute control. PoF combines PoA performance with the security of majority voting (Quorum).

How It Works

PoF uses a rotation model combined with multi-signature verification: 1. Leader Rotation: The Leader with block proposal rights is determined by a deterministic mathematical formula: Leader = Validators[BlockIndex % TotalValidators]. This prevents any node from permanently seizing control. 2. Quorum Voting: For a block to be valid, it needs not only the Leader's signature but also confirmation from a minimum number of nodes in the consortium (typically 2/3 + 1). 3. Sorted Validator List: The list of participating nodes is automatically sorted by ID to ensure consistent block creation scheduling across the network.

Key Features

  • Multi-party Governance

    Eliminates Single Point of Failure. If the current Leader fails, block creation rights automatically transfer to the next node in the cycle.

  • Quorum Voting

    Provides an additional security layer by requiring consensus from the majority of member organizations before committing data.

  • Fairness & Transparency

    Every member organization has equal opportunity to contribute and control the ledger through the predetermined schedule.

Configuration Parameters

Parameter Description Default
min_validators Minimum number of nodes for network operation. 3
block_interval Target block creation cycle. 5.0 seconds
enforce_rotation Mandatory leader rotation after each block. True

Block Verification Flow

graph TD
    A[Block Proposed by Leader] --> B{Verify Leader Identity}
    B -- Correct Leader --> C[Collect Quorum Signatures]
    C --> D{Signatures >= 2/3 + 1?}
    D -- Yes --> E[Commit Block to Ledger]
    D -- No --> F[Reject & Wait for Next Leader]
    B -- Wrong Leader --> G[Reject Block]

Advantages and Limitations

  • Advantages: Suitable for multi-party consortium networks, resistant to domination by a small group, high availability.
  • Limitations: Requires additional network bandwidth for Quorum signature collection compared to PoA, performance slightly degrades when the number of Validators grows too large.