@clduab11/gemini-flow/src/security/zero-trust-architecture.ts

Revolutionary AI agent swarm coordination platform with Google Services integration, multimedia processing, and production-ready monitoring. Features 8 Google AI services, quantum computing capabilities, and enterprise-grade security.

/**
 * Zero-Trust Architecture Implementation
 *
 * Implements comprehensive zero-trust security model with:
 * - Never trust, always verify principle
 * - Least privilege access control
 * - Continuous verification and monitoring
 * - Micro-segmentation and identity-based perimeters
 * - Device trust and endpoint security
 * - Data-centric security controls
 * - Adaptive authentication and authorization
 * - Behavior analytics and risk scoring
 */

import { EventEmitter } from "events";
import { Logger } from "../utils/logger.js";
import crypto from "crypto";
import jwt from "jsonwebtoken";
import { DatabaseConnection } from "../core/sqlite-connection-pool.js";

export interface ZeroTrustPolicy {
  id: string;
  name: string;
  description: string;
  version: string;
  enabled: boolean;

  // Identity and Access Management
  identityVerification: {
    requireMfa: boolean;
    mfaMethods: (
      | "totp"
      | "sms"
      | "email"
      | "push"
      | "biometric"
      | "hardware_token"
    )[];
    continuousAuthentication: boolean;
    sessionTimeout: number; // minutes
    deviceTrustRequired: boolean;
  };

  // Network Security
  networkSegmentation: {
    enabled: boolean;
    defaultDeny: boolean;
    microSegments: NetworkSegment[];
    tunnelRequired: boolean;
    encryptionRequired: boolean;
  };

  // Device Security
  deviceTrust: {
    deviceRegistrationRequired: boolean;
    deviceHealthChecks: boolean;
    allowedDeviceTypes: ("desktop" | "mobile" | "tablet" | "server")[];
    osVersionRequirements: Record<string, string>;
    endpointProtectionRequired: boolean;
  };

  // Application Security
  applicationSecurity: {
    applicationInventory: boolean;
    applicationApproval: boolean;
    runtimeProtection: boolean;
    apiSecurity: boolean;
    dataFlowMonitoring: boolean;
  };

  // Data Security
  dataSecurity: {
    dataClassification: boolean;
    encryptionAtRest: boolean;
    encryptionInTransit: boolean;
    dataLossPreventionEnabled: boolean;
    dataAccessLogging: boolean;
  };

  // Monitoring and Analytics
  monitoring: {
    continuousMonitoring: boolean;
    behaviorAnalytics: boolean;
    riskScoring: boolean;
    anomalyDetection: boolean;
    responseAutomation: boolean;
  };
}

export interface NetworkSegment {
  id: string;
  name: string;
  description: string;
  ipRanges: string[];
  allowedPorts: number[];
  protocols: ("tcp" | "udp" | "icmp")[];
  trustLevel: "untrusted" | "low" | "medium" | "high" | "critical";
  accessRules: AccessRule[];
  monitoring: {
    enabled: boolean;
    logLevel: "basic" | "detailed" | "verbose";
    alertOnAnomalies: boolean;
  };
}

export interface AccessRule {
  id: string;
  name: string;
  source: {
    type: "user" | "device" | "application" | "segment";
    identifiers: string[];
  };
  destination: {
    type: "resource" | "service" | "segment";
    identifiers: string[];
  };
  permissions: string[];
  conditions: AccessCondition[];
  timeRestrictions?: {
    allowedHours: string;
    timeZone: string;
    daysOfWeek: number[];
  };
  riskThreshold: number;
  enabled: boolean;
}

export interface AccessCondition {
  type: "location" | "device_trust" | "user_risk" | "time" | "context";
  operator:
    | "equals"
    | "not_equals"
    | "contains"
    | "greater_than"
    | "less_than"
    | "in_range";
  value: any;
  required: boolean;
}

export interface DeviceTrust {
  deviceId: string;
  userId?: string;
  deviceType: "desktop" | "mobile" | "tablet" | "server";
  operatingSystem: string;
  osVersion: string;
  deviceFingerprint: string;
  enrollmentDate: Date;
  lastSeen: Date;
  trustScore: number; // 0-100
  trustLevel: "untrusted" | "low" | "medium" | "high";
  complianceStatus: {
    patchLevel: "current" | "outdated" | "critical";
    antivirus: boolean;
    encryption: boolean;
    managementAgent: boolean;
    jailbroken: boolean;
  };
  riskFactors: string[];
  certificates: DeviceCertificate[];
}

export interface DeviceCertificate {
  id: string;
  type: "device_identity" | "user_certificate" | "application_certificate";
  issuer: string;
  subject: string;
  validFrom: Date;
  validTo: Date;
  fingerprint: string;
  revoked: boolean;
}

export interface RiskAssessment {
  id: string;
  subjectType: "user" | "device" | "application" | "session";
  subjectId: string;
  assessmentTime: Date;
  riskScore: number; // 0-100
  riskLevel: "low" | "medium" | "high" | "critical";
  riskFactors: RiskFactor[];
  mitigationActions: string[];
  validUntil: Date;
  automaticReassessment: boolean;
}

export interface RiskFactor {
  type: "behavioral" | "contextual" | "technical" | "historical";
  category: string;
  description: string;
  severity: "low" | "medium" | "high" | "critical";
  weight: number;
  evidence: any[];
}

export interface ZeroTrustSession {
  id: string;
  userId: string;
  deviceId: string;
  applicationId?: string;
  startTime: Date;
  lastActivity: Date;
  expiryTime: Date;
  trustScore: number;
  riskLevel: "low" | "medium" | "high" | "critical";
  accessGrants: AccessGrant[];
  verificationEvents: VerificationEvent[];
  behaviorProfile: BehaviorProfile;
  status: "active" | "expired" | "revoked" | "suspended";
}

export interface AccessGrant {
  id: string;
  resource: string;
  permissions: string[];
  grantedAt: Date;
  expiresAt: Date;
  conditions: AccessCondition[];
  lastUsed?: Date;
  usageCount: number;
  maxUsage?: number;
}

export interface VerificationEvent {
  id: string;
  timestamp: Date;
  type: "initial_auth" | "continuous_auth" | "step_up_auth" | "risk_assessment";
  method: string;
  result: "success" | "failure" | "challenge";
  riskScore: number;
  details: any;
}

export interface BehaviorProfile {
  userId: string;
  deviceId: string;
  baseline: {
    typicalLocations: string[];
    workingHours: { start: string; end: string }[];
    commonApplications: string[];
    averageSessionDuration: number;
    accessPatterns: Record<string, number>;
  };
  currentSession: {
    deviationScore: number;
    anomalies: string[];
    riskIndicators: string[];
  };
  historicalData: {
    sessionCount: number;
    averageRiskScore: number;
    incidentCount: number;
    lastUpdate: Date;
  };
}

export class ZeroTrustArchitecture extends EventEmitter {
  private logger: Logger;
  private db: DatabaseConnection;
  private policy: ZeroTrustPolicy;

  // Core components
  private identityProvider: IdentityProvider;
  private deviceManager: DeviceManager;
  private networkController: NetworkController;
  private riskEngine: RiskEngine;
  private policyEngine: PolicyEngine;
  private behaviorAnalytics: BehaviorAnalytics;
  private continuousVerification: ContinuousVerification;

  // State management
  private activeSessions: Map<string, ZeroTrustSession> = new Map();
  private deviceRegistry: Map<string, DeviceTrust> = new Map();
  private networkSegments: Map<string, NetworkSegment> = new Map();
  private accessPolicies: Map<string, AccessRule> = new Map();
  private riskAssessments: Map<string, RiskAssessment> = new Map();

  // Metrics
  private metrics = {
    authenticationAttempts: 0,
    continuousVerifications: 0,
    accessRequests: 0,
    riskAssessments: 0,
    policyViolations: 0,
    deviceRegistrations: 0,
    sessionCreated: 0,
    sessionRevoked: 0,
  };

  constructor(db: DatabaseConnection, policy: ZeroTrustPolicy) {
    super();
    this.logger = new Logger("ZeroTrustArchitecture");
    this.db = db;
    this.policy = policy;

    this.initializeComponents();
    this.startContinuousProcesses();

    this.logger.info("Zero-Trust Architecture initialized", {
      policyVersion: policy.version,
      identityVerification: policy.identityVerification.requireMfa,
      networkSegmentation: policy.networkSegmentation.enabled,
      deviceTrust: policy.deviceTrust.deviceRegistrationRequired,
    });
  }

  /**
   * 🔐 Identity and Access Management
   */

  /**
   * Authenticate user with multi-factor verification
   */
  async authenticateUser(credentials: {
    username: string;
    password?: string;
    mfaToken?: string;
    deviceId: string;
    contextInfo: {
      ipAddress: string;
      userAgent: string;
      location?: {
        latitude: number;
        longitude: number;
        country: string;
        city: string;
      };
    };
  }): Promise<{
    success: boolean;
    sessionId?: string;
    challengeRequired?: {
      type: string;
      methods: string[];
      challengeId: string;
    };
    riskAssessment: RiskAssessment;
    message: string;
  }> {
    try {
      this.metrics.authenticationAttempts++;

      // Step 1: Validate device trust
      const deviceTrust = await this.validateDeviceTrust(credentials.deviceId);
      if (
        !deviceTrust.trusted &&
        this.policy.identityVerification.deviceTrustRequired
      ) {
        return {
          success: false,
          riskAssessment: await this.assessRisk("device", credentials.deviceId),
          message: "Device not trusted - registration required",
        };
      }

      // Step 2: Primary authentication
      const primaryAuth = await this.identityProvider.authenticate(
        credentials.username,
        credentials.password,
      );

      if (!primaryAuth.success) {
        await this.logSecurityEvent("authentication_failed", {
          username: credentials.username,
          deviceId: credentials.deviceId,
          reason: "Invalid credentials",
        });
        return {
          success: false,
          riskAssessment: await this.assessRisk("user", credentials.username),
          message: "Authentication failed",
        };
      }

      // Step 3: Risk assessment
      const riskAssessment = await this.assessAuthenticationRisk({
        userId: primaryAuth.userId,
        deviceId: credentials.deviceId,
        contextInfo: credentials.contextInfo,
      });

      // Step 4: MFA requirement determination
      const mfaRequired =
        this.policy.identityVerification.requireMfa ||
        riskAssessment.riskLevel === "high" ||
        riskAssessment.riskLevel === "critical";

      if (mfaRequired && !credentials.mfaToken) {
        const challengeId = await this.initiateMultiFactorChallenge(
          primaryAuth.userId,
          credentials.deviceId,
        );

        return {
          success: false,
          challengeRequired: {
            type: "mfa",
            methods: this.policy.identityVerification.mfaMethods,
            challengeId,
          },
          riskAssessment,
          message: "Multi-factor authentication required",
        };
      }

      if (mfaRequired && credentials.mfaToken) {
        const mfaValid = await this.identityProvider.verifyMfa(
          primaryAuth.userId,
          credentials.mfaToken,
        );

        if (!mfaValid) {
          return {
            success: false,
            riskAssessment,
            message: "Invalid MFA token",
          };
        }
      }

      // Step 5: Create zero-trust session
      const session = await this.createZeroTrustSession(
        primaryAuth.userId,
        credentials.deviceId,
        riskAssessment,
      );

      await this.logSecurityEvent("authentication_success", {
        userId: primaryAuth.userId,
        deviceId: credentials.deviceId,
        sessionId: session.id,
        riskScore: riskAssessment.riskScore,
      });

      return {
        success: true,
        sessionId: session.id,
        riskAssessment,
        message: "Authentication successful",
      };
    } catch (error) {
      this.logger.error("Authentication failed", { error, credentials });
      return {
        success: false,
        riskAssessment: {
          riskScore: 100,
          riskLevel: "critical",
        } as RiskAssessment,
        message: "Authentication error",
      };
    }
  }

  /**
   * Continuous authentication and session validation
   */
  async validateSession(sessionId: string): Promise<{
    valid: boolean;
    session?: ZeroTrustSession;
    requiresReauth?: boolean;
    riskAssessment?: RiskAssessment;
  }> {
    try {
      const session = this.activeSessions.get(sessionId);
      if (!session) {
        return { valid: false };
      }

      // Check session expiry
      if (session.expiryTime < new Date()) {
        await this.revokeSession(sessionId, "Session expired");
        return { valid: false };
      }

      // Continuous verification
      if (this.policy.identityVerification.continuousAuthentication) {
        const currentRisk = await this.assessRisk("session", sessionId);

        // Check if risk level has increased
        if (
          currentRisk.riskLevel === "high" ||
          currentRisk.riskLevel === "critical"
        ) {
          return {
            valid: true,
            session,
            requiresReauth: true,
            riskAssessment: currentRisk,
          };
        }

        // Update session risk
        session.riskLevel = currentRisk.riskLevel;
        session.trustScore = 100 - currentRisk.riskScore;
      }

      // Update last activity
      session.lastActivity = new Date();
      this.metrics.continuousVerifications++;

      return {
        valid: true,
        session,
      };
    } catch (error) {
      this.logger.error("Session validation failed", { error, sessionId });
      return { valid: false };
    }
  }

  /**
   * Authorize access to resources
   */
  async authorizeAccess(
    sessionId: string,
    resource: string,
    action: string,
    contextInfo?: any,
  ): Promise<{
    authorized: boolean;
    accessGrant?: AccessGrant;
    reason: string;
    conditions?: AccessCondition[];
  }> {
    try {
      this.metrics.accessRequests++;

      const session = this.activeSessions.get(sessionId);
      if (!session || session.status !== "active") {
        return {
          authorized: false,
          reason: "Invalid or inactive session",
        };
      }

      // Find applicable access policies
      const applicablePolicies = Array.from(
        this.accessPolicies.values(),
      ).filter((policy) =>
        this.policyEngine.matches(policy, {
          userId: session.userId,
          deviceId: session.deviceId,
          resource,
          action,
          contextInfo,
        }),
      );

      if (applicablePolicies.length === 0) {
        await this.logSecurityEvent("access_denied", {
          sessionId,
          resource,
          action,
          reason: "No applicable policy",
        });
        return {
          authorized: false,
          reason: "Access not permitted by policy",
        };
      }

      // Evaluate policies and conditions
      const policyResult = await this.policyEngine.evaluate(
        applicablePolicies,
        session,
        { resource, action, contextInfo },
      );

      if (!policyResult.allowed) {
        this.metrics.policyViolations++;
        await this.logSecurityEvent("access_denied", {
          sessionId,
          resource,
          action,
          reason: policyResult.reason,
          violatedPolicies: policyResult.violatedPolicies,
        });
        return {
          authorized: false,
          reason: policyResult.reason,
        };
      }

      // Create access grant
      const accessGrant: AccessGrant = {
        id: crypto.randomUUID(),
        resource,
        permissions: [action],
        grantedAt: new Date(),
        expiresAt: new Date(Date.now() + 3600000), // 1 hour
        conditions: policyResult.conditions || [],
        usageCount: 0,
      };

      session.accessGrants.push(accessGrant);

      await this.logSecurityEvent("access_granted", {
        sessionId,
        resource,
        action,
        grantId: accessGrant.id,
      });

      return {
        authorized: true,
        accessGrant,
        reason: "Access granted by policy",
        conditions: accessGrant.conditions,
      };
    } catch (error) {
      this.logger.error("Authorization failed", {
        error,
        sessionId,
        resource,
        action,
      });
      return {
        authorized: false,
        reason: "Authorization error",
      };
    }
  }

  /**
   * 📱 Device Trust and Management
   */

  /**
   * Register new device
   */
  async registerDevice(
    deviceInfo: {
      deviceId: string;
      userId?: string;
      deviceType: "desktop" | "mobile" | "tablet" | "server";
      operatingSystem: string;
      osVersion: string;
      deviceFingerprint: string;
    },
    enrollmentMethod: "manual" | "automated" | "bulk",
  ): Promise<{
    success: boolean;
    deviceTrust?: DeviceTrust;
    enrollmentToken?: string;
    message: string;
  }> {
    try {
      this.metrics.deviceRegistrations++;

      // Check if device already exists
      if (this.deviceRegistry.has(deviceInfo.deviceId)) {
        return {
          success: false,
          message: "Device already registered",
        };
      }

      // Validate OS version requirements
      const osRequirements =
        this.policy.deviceTrust.osVersionRequirements[
          deviceInfo.operatingSystem
        ];
      if (
        osRequirements &&
        !this.meetsVersionRequirement(deviceInfo.osVersion, osRequirements)
      ) {
        return {
          success: false,
          message: `OS version ${deviceInfo.osVersion} does not meet minimum requirement ${osRequirements}`,
        };
      }

      // Create device trust record
      const deviceTrust: DeviceTrust = {
        deviceId: deviceInfo.deviceId,
        userId: deviceInfo.userId,
        deviceType: deviceInfo.deviceType,
        operatingSystem: deviceInfo.operatingSystem,
        osVersion: deviceInfo.osVersion,
        deviceFingerprint: deviceInfo.deviceFingerprint,
        enrollmentDate: new Date(),
        lastSeen: new Date(),
        trustScore: 50, // Initial trust score
        trustLevel: "low",
        complianceStatus: {
          patchLevel: "current",
          antivirus: false,
          encryption: false,
          managementAgent: false,
          jailbroken: false,
        },
        riskFactors: [],
        certificates: [],
      };

      // Perform initial device assessment
      const assessment = await this.assessDeviceCompliance(deviceTrust);
      deviceTrust.complianceStatus = assessment.compliance;
      deviceTrust.trustScore = assessment.trustScore;
      deviceTrust.trustLevel = this.calculateTrustLevel(assessment.trustScore);
      deviceTrust.riskFactors = assessment.riskFactors;

      this.deviceRegistry.set(deviceInfo.deviceId, deviceTrust);

      // Store in database
      await this.storeDeviceTrust(deviceTrust);

      // Generate enrollment token if needed
      let enrollmentToken: string | undefined;
      if (enrollmentMethod === "manual" && deviceTrust.trustLevel === "low") {
        enrollmentToken = await this.generateEnrollmentToken(
          deviceInfo.deviceId,
        );
      }

      await this.logSecurityEvent("device_registered", {
        deviceId: deviceInfo.deviceId,
        userId: deviceInfo.userId,
        trustLevel: deviceTrust.trustLevel,
        enrollmentMethod,
      });

      return {
        success: true,
        deviceTrust,
        enrollmentToken,
        message: "Device registered successfully",
      };
    } catch (error) {
      this.logger.error("Device registration failed", { error, deviceInfo });
      return {
        success: false,
        message: "Device registration error",
      };
    }
  }

  /**
   * Validate device trust
   */
  async validateDeviceTrust(deviceId: string): Promise<{
    trusted: boolean;
    trustLevel: string;
    trustScore: number;
    complianceIssues: string[];
    requiresUpdate: boolean;
  }> {
    try {
      const device = this.deviceRegistry.get(deviceId);
      if (!device) {
        return {
          trusted: false,
          trustLevel: "untrusted",
          trustScore: 0,
          complianceIssues: ["Device not registered"],
          requiresUpdate: true,
        };
      }

      // Check if device trust needs updating
      const lastAssessment = new Date(device.lastSeen);
      const now = new Date();
      const hoursSinceLastAssessment =
        (now.getTime() - lastAssessment.getTime()) / (1000 * 60 * 60);

      if (hoursSinceLastAssessment > 24) {
        // Perform fresh compliance assessment
        const assessment = await this.assessDeviceCompliance(device);
        device.complianceStatus = assessment.compliance;
        device.trustScore = assessment.trustScore;
        device.trustLevel = this.calculateTrustLevel(assessment.trustScore);
        device.riskFactors = assessment.riskFactors;
        device.lastSeen = now;

        await this.storeDeviceTrust(device);
      }

      const complianceIssues: string[] = [];
      if (device.complianceStatus.patchLevel === "critical")
        complianceIssues.push("Critical patches missing");
      if (!device.complianceStatus.antivirus)
        complianceIssues.push("Antivirus not detected");
      if (!device.complianceStatus.encryption)
        complianceIssues.push("Disk encryption not enabled");
      if (device.complianceStatus.jailbroken)
        complianceIssues.push("Device is jailbroken/rooted");

      const trusted =
        device.trustLevel !== "untrusted" && complianceIssues.length === 0;

      return {
        trusted,
        trustLevel: device.trustLevel,
        trustScore: device.trustScore,
        complianceIssues,
        requiresUpdate: hoursSinceLastAssessment > 24,
      };
    } catch (error) {
      this.logger.error("Device trust validation failed", { error, deviceId });
      return {
        trusted: false,
        trustLevel: "untrusted",
        trustScore: 0,
        complianceIssues: ["Validation error"],
        requiresUpdate: true,
      };
    }
  }

  /**
   * 🌐 Network Segmentation and Control
   */

  /**
   * Create network micro-segment
   */
  async createNetworkSegment(
    segmentConfig: Omit<NetworkSegment, "id">,
  ): Promise<string> {
    const segmentId = crypto.randomUUID();
    const segment: NetworkSegment = {
      id: segmentId,
      ...segmentConfig,
    };

    this.networkSegments.set(segmentId, segment);

    // Configure network infrastructure
    await this.networkController.createSegment(segment);

    await this.logSecurityEvent("network_segment_created", {
      segmentId,
      name: segment.name,
      trustLevel: segment.trustLevel,
    });

    return segmentId;
  }

  /**
   * Authorize network access
   */
  async authorizeNetworkAccess(
    sourceId: string,
    sourceType: "user" | "device" | "application",
    destinationSegment: string,
    protocol: "tcp" | "udp" | "icmp",
    port: number,
  ): Promise<{
    authorized: boolean;
    reason: string;
    temporaryAccess?: boolean;
    duration?: number;
  }> {
    try {
      const segment = this.networkSegments.get(destinationSegment);
      if (!segment) {
        return {
          authorized: false,
          reason: "Destination segment not found",
        };
      }

      // Check default deny policy
      if (this.policy.networkSegmentation.defaultDeny) {
        // Must have explicit allow rule
        const allowedByRule = segment.accessRules.some(
          (rule) =>
            rule.enabled &&
            rule.source.type === sourceType &&
            rule.source.identifiers.includes(sourceId),
        );

        if (!allowedByRule) {
          return {
            authorized: false,
            reason: "No explicit allow rule found",
          };
        }
      }

      // Check protocol and port restrictions
      if (
        !segment.protocols.includes(protocol) ||
        (segment.allowedPorts.length > 0 &&
          !segment.allowedPorts.includes(port))
      ) {
        return {
          authorized: false,
          reason: "Protocol or port not allowed",
        };
      }

      // Evaluate access conditions
      const applicableRules = segment.accessRules.filter(
        (rule) =>
          rule.enabled &&
          rule.source.type === sourceType &&
          rule.source.identifiers.includes(sourceId),
      );

      for (const rule of applicableRules) {
        const conditionResult = await this.evaluateAccessConditions(
          rule.conditions,
          {
            sourceId,
            sourceType,
            timestamp: new Date(),
          },
        );

        if (!conditionResult.satisfied) {
          return {
            authorized: false,
            reason: `Access condition not satisfied: ${conditionResult.failedCondition}`,
          };
        }
      }

      await this.logSecurityEvent("network_access_granted", {
        sourceId,
        sourceType,
        destinationSegment,
        protocol,
        port,
      });

      return {
        authorized: true,
        reason: "Access granted by network policy",
      };
    } catch (error) {
      this.logger.error("Network access authorization failed", {
        error,
        sourceId,
        destinationSegment,
      });
      return {
        authorized: false,
        reason: "Authorization error",
      };
    }
  }

  /**
   * 📈 Risk Assessment and Monitoring
   */

  /**
   * Comprehensive risk assessment
   */
  async assessRisk(
    subjectType: "user" | "device" | "application" | "session",
    subjectId: string,
  ): Promise<RiskAssessment> {
    try {
      this.metrics.riskAssessments++;

      const riskFactors: RiskFactor[] = [];
      let baseRiskScore = 0;

      switch (subjectType) {
        case "user":
          riskFactors.push(...(await this.assessUserRisk(subjectId)));
          break;
        case "device":
          riskFactors.push(...(await this.assessDeviceRisk(subjectId)));
          break;
        case "application":
          riskFactors.push(...(await this.assessApplicationRisk(subjectId)));
          break;
        case "session":
          riskFactors.push(...(await this.assessSessionRisk(subjectId)));
          break;
      }

      // Calculate overall risk score
      const totalWeight = riskFactors.reduce(
        (sum, factor) => sum + factor.weight,
        0,
      );
      const weightedScore = riskFactors.reduce((sum, factor) => {
        const severityMultiplier = {
          low: 1,
          medium: 2,
          high: 3,
          critical: 4,
        }[factor.severity];
        return sum + factor.weight * severityMultiplier;
      }, 0);

      const riskScore =
        totalWeight > 0 ? Math.min(100, (weightedScore / totalWeight) * 25) : 0;
      const riskLevel = this.calculateRiskLevel(riskScore);

      const assessment: RiskAssessment = {
        id: crypto.randomUUID(),
        subjectType,
        subjectId,
        assessmentTime: new Date(),
        riskScore,
        riskLevel,
        riskFactors,
        mitigationActions: this.generateMitigationActions(riskFactors),
        validUntil: new Date(Date.now() + 3600000), // 1 hour
        automaticReassessment: riskLevel === "high" || riskLevel === "critical",
      };

      this.riskAssessments.set(`${subjectType}:${subjectId}`, assessment);

      if (riskLevel === "high" || riskLevel === "critical") {
        await this.logSecurityEvent("high_risk_detected", {
          subjectType,
          subjectId,
          riskScore,
          riskLevel,
          riskFactors: riskFactors.map((f) => f.category),
        });

        this.emit("high_risk_detected", assessment);
      }

      return assessment;
    } catch (error) {
      this.logger.error("Risk assessment failed", {
        error,
        subjectType,
        subjectId,
      });

      // Return high risk assessment on error
      return {
        id: crypto.randomUUID(),
        subjectType,
        subjectId,
        assessmentTime: new Date(),
        riskScore: 90,
        riskLevel: "high",
        riskFactors: [
          {
            type: "technical",
            category: "assessment_error",
            description: "Risk assessment failed",
            severity: "high",
            weight: 1,
            evidence: [],
          },
        ],
        mitigationActions: ["Manual review required"],
        validUntil: new Date(Date.now() + 300000), // 5 minutes
        automaticReassessment: true,
      };
    }
  }

  /**
   * Get security metrics and status
   */
  getSecurityStatus(): {
    metrics: typeof this.metrics;
    activeSessions: number;
    registeredDevices: number;
    networkSegments: number;
    highRiskAssessments: number;
    policyViolations: number;
  } {
    const highRiskAssessments = Array.from(
      this.riskAssessments.values(),
    ).filter(
      (assessment) =>
        assessment.riskLevel === "high" || assessment.riskLevel === "critical",
    ).length;

    return {
      metrics: { ...this.metrics },
      activeSessions: this.activeSessions.size,
      registeredDevices: this.deviceRegistry.size,
      networkSegments: this.networkSegments.size,
      highRiskAssessments,
      policyViolations: this.metrics.policyViolations,
    };
  }

  /**
   * Private implementation methods
   */

  private initializeComponents(): void {
    this.identityProvider = new IdentityProvider(this.db);
    this.deviceManager = new DeviceManager(this.db, this.policy);
    this.networkController = new NetworkController(this.policy);
    this.riskEngine = new RiskEngine(this.db);
    this.policyEngine = new PolicyEngine(this.policy);
    this.behaviorAnalytics = new BehaviorAnalytics(this.db);
    this.continuousVerification = new ContinuousVerification(this.policy);
  }

  private startContinuousProcesses(): void {
    // Continuous risk assessment
    setInterval(async () => {
      await this.performContinuousRiskAssessment();
    }, 300000); // Every 5 minutes

    // Session cleanup
    setInterval(async () => {
      await this.cleanupExpiredSessions();
    }, 600000); // Every 10 minutes

    // Device trust updates
    setInterval(async () => {
      await this.updateDeviceTrustScores();
    }, 1800000); // Every 30 minutes
  }

  private async createZeroTrustSession(
    userId: string,
    deviceId: string,
    riskAssessment: RiskAssessment,
  ): Promise<ZeroTrustSession> {
    const sessionId = crypto.randomUUID();
    const now = new Date();

    const session: ZeroTrustSession = {
      id: sessionId,
      userId,
      deviceId,
      startTime: now,
      lastActivity: now,
      expiryTime: new Date(
        now.getTime() + this.policy.identityVerification.sessionTimeout * 60000,
      ),
      trustScore: 100 - riskAssessment.riskScore,
      riskLevel: riskAssessment.riskLevel,
      accessGrants: [],
      verificationEvents: [
        {
          id: crypto.randomUUID(),
          timestamp: now,
          type: "initial_auth",
          method: "password_mfa",
          result: "success",
          riskScore: riskAssessment.riskScore,
          details: { deviceId, userId },
        },
      ],
      behaviorProfile: await this.behaviorAnalytics.getProfile(
        userId,
        deviceId,
      ),
      status: "active",
    };

    this.activeSessions.set(sessionId, session);
    this.metrics.sessionCreated++;

    return session;
  }

  private async revokeSession(
    sessionId: string,
    reason: string,
  ): Promise<void> {
    const session = this.activeSessions.get(sessionId);
    if (session) {
      session.status = "revoked";
      this.activeSessions.delete(sessionId);
      this.metrics.sessionRevoked++;

      await this.logSecurityEvent("session_revoked", {
        sessionId,
        userId: session.userId,
        reason,
      });
    }
  }

  // Additional helper methods would be implemented here...

  private async assessAuthenticationRisk(
    context: any,
  ): Promise<RiskAssessment> {
    // Implementation for authentication risk assessment
    return {
      id: crypto.randomUUID(),
      subjectType: "user",
      subjectId: context.userId,
      assessmentTime: new Date(),
      riskScore: 25,
      riskLevel: "low",
      riskFactors: [],
      mitigationActions: [],
      validUntil: new Date(Date.now() + 3600000),
      automaticReassessment: false,
    };
  }

  private async initiateMultiFactorChallenge(
    userId: string,
    deviceId: string,
  ): Promise<string> {
    // Implementation for MFA challenge
    return crypto.randomUUID();
  }

  private async assessDeviceCompliance(device: DeviceTrust): Promise<any> {
    // Implementation for device compliance assessment
    return {
      compliance: device.complianceStatus,
      trustScore: 75,
      riskFactors: [],
    };
  }

  private calculateTrustLevel(
    trustScore: number,
  ): "untrusted" | "low" | "medium" | "high" {
    if (trustScore < 25) return "untrusted";
    if (trustScore < 50) return "low";
    if (trustScore < 75) return "medium";
    return "high";
  }

  private calculateRiskLevel(
    riskScore: number,
  ): "low" | "medium" | "high" | "critical" {
    if (riskScore < 25) return "low";
    if (riskScore < 50) return "medium";
    if (riskScore < 75) return "high";
    return "critical";
  }

  private meetsVersionRequirement(
    currentVersion: string,
    requiredVersion: string,
  ): boolean {
    // Simple version comparison - in production would use proper semver comparison
    return currentVersion >= requiredVersion;
  }

  private async generateEnrollmentToken(deviceId: string): Promise<string> {
    return jwt.sign({ deviceId, type: "enrollment" }, "secret", {
      expiresIn: "24h",
    });
  }

  private async storeDeviceTrust(device: DeviceTrust): Promise<void> {
    // Store device trust in database
  }

  private async evaluateAccessConditions(
    conditions: AccessCondition[],
    context: any,
  ): Promise<any> {
    return { satisfied: true, failedCondition: null };
  }

  private async assessUserRisk(userId: string): Promise<RiskFactor[]> {
    return [];
  }

  private async assessDeviceRisk(deviceId: string): Promise<RiskFactor[]> {
    return [];
  }

  private async assessApplicationRisk(
    applicationId: string,
  ): Promise<RiskFactor[]> {
    return [];
  }

  private async assessSessionRisk(sessionId: string): Promise<RiskFactor[]> {
    return [];
  }

  private generateMitigationActions(riskFactors: RiskFactor[]): string[] {
    return riskFactors.map((factor) => `Mitigate ${factor.category}`);
  }

  private async performContinuousRiskAssessment(): Promise<void> {
    // Implementation for continuous risk assessment
  }

  private async cleanupExpiredSessions(): Promise<void> {
    const now = new Date();
    for (const [sessionId, session] of this.activeSessions) {
      if (session.expiryTime < now) {
        await this.revokeSession(sessionId, "Session expired");
      }
    }
  }

  private async updateDeviceTrustScores(): Promise<void> {
    // Implementation for updating device trust scores
  }

  private async logSecurityEvent(
    eventType: string,
    details: any,
  ): Promise<void> {
    await this.db.executeQuery(
      "INSERT INTO security_events (id, event_type, details, timestamp) VALUES (?, ?, ?, ?)",
      [
        crypto.randomUUID(),
        eventType,
        JSON.stringify(details),
        new Date().toISOString(),
      ],
    );
  }
}

// Supporting classes - these would be fully implemented in production
class IdentityProvider {
  constructor(private db: DatabaseConnection) {}

  async authenticate(username: string, password?: string): Promise<any> {
    return { success: true, userId: username };
  }

  async verifyMfa(userId: string, token: string): Promise<boolean> {
    return true;
  }
}

class DeviceManager {
  constructor(
    private db: DatabaseConnection,
    private policy: ZeroTrustPolicy,
  ) {}
}

class NetworkController {
  constructor(private policy: ZeroTrustPolicy) {}

  async createSegment(segment: NetworkSegment): Promise<void> {
    // Implementation would configure actual network infrastructure
  }
}

class RiskEngine {
  constructor(private db: DatabaseConnection) {}
}

class PolicyEngine {
  constructor(private policy: ZeroTrustPolicy) {}

  matches(policy: AccessRule, context: any): boolean {
    return true; // Simplified implementation
  }

  async evaluate(
    policies: AccessRule[],
    session: ZeroTrustSession,
    context: any,
  ): Promise<any> {
    return {
      allowed: true,
      reason: "Policy evaluation passed",
      conditions: [],
    };
  }
}

class BehaviorAnalytics {
  constructor(private db: DatabaseConnection) {}

  async getProfile(userId: string, deviceId: string): Promise<BehaviorProfile> {
    return {
      userId,
      deviceId,
      baseline: {
        typicalLocations: [],
        workingHours: [],
        commonApplications: [],
        averageSessionDuration: 0,
        accessPatterns: {},
      },
      currentSession: {
        deviationScore: 0,
        anomalies: [],
        riskIndicators: [],
      },
      historicalData: {
        sessionCount: 0,
        averageRiskScore: 0,
        incidentCount: 0,
        lastUpdate: new Date(),
      },
    };
  }
}

class ContinuousVerification {
  constructor(private policy: ZeroTrustPolicy) {}
}

export { ZeroTrustArchitecture };
export type {
  ZeroTrustPolicy,
  NetworkSegment,
  AccessRule,
  DeviceTrust,
  RiskAssessment,
  ZeroTrustSession,
};