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

Operation	Latency
Full Auth (Turbo)	1.28ms
Full Auth (Standard)	633µs
Session Resume	50µs
Cached Proof Verify	32µs

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.