Session Resume at 50µs:
Instant Re-Authentication

When a user returns to your application, why make them wait? H33's new session resume feature re-authenticates returning users in just 50 microseconds—that's 4.4x faster than a full authentication and essentially instant from a user's perspective.

How Session Resume Works

Traditional authentication re-verifies everything on each request: biometrics, cryptographic proofs, and attestations. This is wasteful when the user's context hasn't changed.

Session resume takes a smarter approach:

• Context preservation: Session state is encrypted and cached server-side
• Cryptographic binding: Session tokens are bound to device fingerprints
• Proof reuse: Valid ZK proofs are cached and verified in 32µs
• Delta detection: Only re-verify what's actually changed

// First authentication - full verification
const initial = await h33.auth.fullStack({
  userId: 'user_123',
  biometric: faceData,
  mode: 'turbo'
});
// 1.28ms - creates session context

// Session resume - lightning fast
const resumed = await h33.session.resume({
  sessionId: initial.sessionId,
  deviceFingerprint: fingerprint
});
// 50µs - verifies cached context

Security Without Compromise

Speed doesn't mean sacrificing security. Session resume maintains full cryptographic verification:

• Session tokens are signed with Dilithium3 (post-quantum secure)
• Device binding prevents session hijacking across devices
• Time-limited validity with configurable expiration
• Anomaly detection triggers full re-authentication when needed

When Full Auth is Required

Session resume automatically falls back to full authentication when:

• Session has expired
• Device fingerprint doesn't match
• IP geolocation changes significantly
• Risk score exceeds threshold
• Sensitive operation is requested

This adaptive approach gives you speed for normal operations and full security when it matters.

Performance Comparison

Implementation Guide

// Configure session management
const sessionManager = h33.createSessionManager({
  ttl: '24h',           // Session lifetime
  resumeWindow: '1h',   // Resume without re-auth
  deviceBinding: true,  // Require device match
  riskThreshold: 0.7    // Trigger full auth above this
});

// Middleware for automatic session handling
app.use(sessionManager.middleware());

// In your routes, authentication is automatic
app.get('/dashboard', async (req, res) => {
  // req.auth is populated - either from resume (50µs)
  // or full auth (1.28ms) based on context
  const user = req.auth.user;
  // ...
});

Real-World Impact

For a typical user session with 50 API calls:

• Without session resume: 50 × 1.28ms = 11,000µs total auth overhead
• With session resume: 1 × 1.28ms + 49 × 50µs = 2,670µs total
• Savings: 76% reduction in authentication latency

For high-frequency applications like real-time collaboration or gaming, this difference is transformative.