@zenithcore/core/src/protocol/quantumConsensus.ts

Core functionality for ZenithKernel framework

/**
 * Quantum Consensus Module for Zenith
 * 
 * This module implements Byzantine agreement, leader election, and distributed key generation
 * using quantum state vectors and zero-knowledge proofs.
 */

import { QuantumZKP, QuantumStateVector } from 'quantum-zkp-sdk/src/qzkp';
import { QZKProofResult } from './qzkpClient';
import { EventEmitter } from 'events';

// Constants
const DEFAULT_QUBIT_COUNT = 8;
const DEFAULT_VOTING_ROUNDS = 3;
const DEFAULT_THRESHOLD = 0.67; // 2/3 majority

/**
 * Node state in the consensus process
 */
export interface ConsensusNodeState {
  nodeId: string;
  measurements: number[];
  entanglement: number;
  coherence: number;
  isLeader: boolean;
  vote: boolean;
  timestamp: number;
}

/**
 * Result of a consensus round
 */
export interface ConsensusResult {
  success: boolean;
  leader: string;
  measurements: number[];
  votes: Record<string, boolean>;
  threshold: number;
  votePercentage: number;
  round: number;
  timestamp: number;
}

/**
 * Result of the key generation process
 */
export interface KeygenResult {
  publicKey: string;
  measurements: number[];
  entropy: number;
  timestamp: number;
}

/**
 * Complete result of the quantum pipeline
 */
export interface QuantumPipelineResult {
  leader: ConsensusNodeState;
  keygen: KeygenResult;
  consensus: ConsensusResult;
  consensusValid: boolean;
  zk: {
    proof: QZKProofResult;
    signals: number[];
    valid: boolean;
  };
}

/**
 * Quantum Consensus class for Byzantine agreement and leader election
 */
export class QuantumConsensus extends EventEmitter {
  private nodes: Map<string, ConsensusNodeState> = new Map();
  private qzkp: QuantumZKP;
  private currentRound: number = 0;
  private votingRounds: number;
  private threshold: number;
  private qubitCount: number;
  private leader: string | null = null;
  private consensusReached: boolean = false;
  private keygenResult: KeygenResult | null = null;

  /**
   * Create a new QuantumConsensus instance
   * @param qubitCount Number of qubits to use for measurements
   * @param votingRounds Number of voting rounds for consensus
   * @param threshold Threshold for consensus (percentage as decimal)
   */
  constructor(
    qubitCount: number = DEFAULT_QUBIT_COUNT,
    votingRounds: number = DEFAULT_VOTING_ROUNDS,
    threshold: number = DEFAULT_THRESHOLD
  ) {
    super();
    this.qubitCount = qubitCount;
    this.votingRounds = votingRounds;
    this.threshold = threshold;
    this.qzkp = new QuantumZKP(qubitCount);
  }

  /**
   * Register a node in the consensus network
   * @param nodeId Unique identifier for the node
   * @returns The node's initial state
   */
  registerNode(nodeId: string): ConsensusNodeState {
    // Generate random measurements (simulating quantum measurement)
    const measurements = Array(this.qubitCount).fill(0).map(() => Math.random() < 0.5 ? 0 : 1);
    
    // Calculate entanglement and coherence
    const entanglement = this.calculateEntanglement(measurements);
    const coherence = this.calculateCoherence(measurements);
    
    const nodeState: ConsensusNodeState = {
      nodeId,
      measurements,
      entanglement,
      coherence,
      isLeader: false,
      vote: false,
      timestamp: Date.now()
    };
    
    this.nodes.set(nodeId, nodeState);
    this.emit('nodeRegistered', nodeState);
    
    return nodeState;
  }

  /**
   * Run leader election based on quantum measurements
   * @returns The elected leader's node ID
   */
  runLeaderElection(): string {
    if (this.nodes.size === 0) {
      throw new Error('No nodes registered for leader election');
    }
    
    // Find the node with the highest entanglement
    let maxEntanglement = -1;
    let leaderId = '';
    
    for (const [nodeId, state] of this.nodes.entries()) {
      if (state.entanglement > maxEntanglement) {
        maxEntanglement = state.entanglement;
        leaderId = nodeId;
      }
    }
    
    // Update the leader status
    for (const [nodeId, state] of this.nodes.entries()) {
      state.isLeader = (nodeId === leaderId);
    }
    
    this.leader = leaderId;
    this.emit('leaderElected', this.nodes.get(leaderId));
    
    return leaderId;
  }

  /**
   * Submit a vote for the current consensus round
   * @param nodeId The voting node's ID
   * @param vote The node's vote (true = agree, false = disagree)
   */
  submitVote(nodeId: string, vote: boolean): void {
    const node = this.nodes.get(nodeId);
    if (!node) {
      throw new Error(`Node ${nodeId} not registered`);
    }
    
    node.vote = vote;
    this.emit('voteSubmitted', { nodeId, vote });
  }

  /**
   * Run a single round of Byzantine consensus
   * @returns Result of the consensus round
   */
  runConsensusRound(): ConsensusResult {
    if (!this.leader) {
      throw new Error('Leader not elected');
    }
    
    // Count votes
    let agreeCount = 0;
    const votes: Record<string, boolean> = {};
    
    for (const [nodeId, state] of this.nodes.entries()) {
      votes[nodeId] = state.vote;
      if (state.vote) {
        agreeCount++;
      }
    }
    
    // Calculate vote percentage
    const votePercentage = agreeCount / this.nodes.size;
    const success = votePercentage >= this.threshold;
    
    // Create consensus measurements by combining leader's measurements
    // with a representation of the voting results
    const leaderState = this.nodes.get(this.leader)!;
    const measurements = [...leaderState.measurements];
    
    // Add voting result to measurements (replace last bit with consensus result)
    if (measurements.length > 0) {
      measurements[measurements.length - 1] = success ? 1 : 0;
    }
    
    const result: ConsensusResult = {
      success,
      leader: this.leader,
      measurements,
      votes,
      threshold: this.threshold,
      votePercentage,
      round: ++this.currentRound,
      timestamp: Date.now()
    };
    
    this.consensusReached = success;
    this.emit('consensusRound', result);
    
    return result;
  }

  /**
   * Generate a distributed key based on consensus measurements
   * @returns Key generation result
   */
  generateDistributedKey(): KeygenResult {
    if (!this.consensusReached) {
      throw new Error('Consensus not reached');
    }
    
    // Combine measurements from all nodes to create a seed
    const combinedMeasurements: number[] = Array(this.qubitCount).fill(0);
    
    for (const state of this.nodes.values()) {
      for (let i = 0; i < this.qubitCount; i++) {
        // XOR the measurements
        combinedMeasurements[i] ^= state.measurements[i];
      }
    }
    
    // Calculate entropy of the combined measurements
    const entropy = this.calculateEntropy(combinedMeasurements);
    
    // Generate a public key from the measurements
    const publicKey = this.measurementsToKey(combinedMeasurements);
    
    const result: KeygenResult = {
      publicKey,
      measurements: combinedMeasurements,
      entropy,
      timestamp: Date.now()
    };
    
    this.keygenResult = result;
    this.emit('keyGenerated', result);
    
    return result;
  }

  /**
   * Run the complete quantum pipeline
   * @param input Input data as Uint8Array
   * @returns Complete pipeline result
   */
  async runQuantumPipeline(input: Uint8Array): Promise<QuantumPipelineResult> {
    // Register nodes (simulating a network of 5 nodes)
    const nodeIds = ['node1', 'node2', 'node3', 'node4', 'node5'];
    for (const nodeId of nodeIds) {
      this.registerNode(nodeId);
    }
    
    // Run leader election
    const leaderId = this.runLeaderElection();
    const leaderState = this.nodes.get(leaderId)!;
    
    // Simulate voting (all nodes agree with the leader)
    for (const nodeId of nodeIds) {
      this.submitVote(nodeId, true);
    }
    
    // Run consensus
    const consensusResult = this.runConsensusRound();
    
    // Generate distributed key
    const keygenResult = this.generateDistributedKey();
    
    // Generate ZK proof from the input and consensus measurements
    const chunkId = `consensus-${Date.now()}`;
    const qzkp = new QuantumZKP(this.qubitCount);
    
    // Convert input to quantum vector
    const vector = Array.from(input).map(b => b / 255);
    
    // Generate proof
    const proof = qzkp.proveVectorKnowledge(vector, chunkId);
    
    // Verify the proof
    const isValid = qzkp.verifyVectorProof(vector, chunkId, proof);
    
    // Create signals for the ZK proof (combining input with consensus measurements)
    const signals = [...consensusResult.measurements, ...Array.from(input).slice(0, 8)];
    
    return {
      leader: leaderState,
      keygen: keygenResult,
      consensus: consensusResult,
      consensusValid: consensusResult.success,
      zk: {
        proof: {
          chunk_id: chunkId,
          entropy: this.calculateEntropy(vector),
          commitment: proof.commitment,
          proof: {
            coherence: proof.coherence,
            entanglement: proof.entanglement,
            timestamp: Date.now()
          }
        },
        signals,
        valid: isValid
      }
    };
  }

  // Helper methods
  
  /**
   * Calculate entanglement from measurements
   */
  private calculateEntanglement(measurements: number[]): number {
    if (measurements.length === 0) return 0;
    
    // Simple entanglement metric: count transitions between 0 and 1
    let transitions = 0;
    for (let i = 1; i < measurements.length; i++) {
      if (measurements[i] !== measurements[i-1]) {
        transitions++;
      }
    }
    
    return transitions / (measurements.length - 1);
  }
  
  /**
   * Calculate coherence from measurements
   */
  private calculateCoherence(measurements: number[]): number {
    if (measurements.length === 0) return 0;
    
    // Simple coherence metric: proportion of 1s
    const sum = measurements.reduce((acc, val) => acc + val, 0);
    return sum / measurements.length;
  }
  
  /**
   * Calculate entropy from measurements or vector
   */
  private calculateEntropy(vector: number[]): number {
    if (vector.length === 0) return 0;
    
    // For binary measurements, use Shannon entropy
    if (vector.every(v => v === 0 || v === 1)) {
      const ones = vector.filter(v => v === 1).length;
      const zeros = vector.length - ones;
      
      if (ones === 0 || zeros === 0) return 0;
      
      const p1 = ones / vector.length;
      const p0 = zeros / vector.length;
      
      return -(p0 * Math.log2(p0) + p1 * Math.log2(p1));
    }
    
    // For continuous values, use a binned approach
    const bins = 10;
    const counts = new Array(bins).fill(0);
    
    for (const val of vector) {
      const binIndex = Math.min(Math.floor(val * bins), bins - 1);
      counts[binIndex]++;
    }
    
    let entropy = 0;
    for (const count of counts) {
      if (count === 0) continue;
      const p = count / vector.length;
      entropy -= p * Math.log2(p);
    }
    
    return entropy / Math.log2(bins); // Normalize to 0-1
  }
  
  /**
   * Convert measurements to a key
   */
  private measurementsToKey(measurements: number[]): string {
    // Convert binary measurements to hex string
    let hexString = '';
    for (let i = 0; i < measurements.length; i += 4) {
      let nibble = 0;
      for (let j = 0; j < 4 && i + j < measurements.length; j++) {
        nibble |= (measurements[i + j] << j);
      }
      hexString += nibble.toString(16);
    }
    
    return hexString.padStart(Math.ceil(measurements.length / 4), '0');
  }
}