> For the complete documentation index, see [llms.txt](https://docs.zer0.build/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.zer0.build/core-concepts/privacy-architecture.md). # Privacy Architecture zer0's privacy architecture is built on three pillars: **zero-knowledge proofs**, **Tor network routing**, and **on-device computation**. Together, they create a fortress where even we can't see what you're doing. *** ## 🏗️ Architecture Overview ``` ┌─────────────────────────────────────────────────────────┐ │ zer0 Browser │ ├─────────────────────────────────────────────────────────┤ │ │ │ ┌──────────────┐ ┌──────────────┐ ┌──────────────┐ │ │ │ Chromium │ │ AI Agents │ │ $zer0 │ │ │ │ Renderer │ │ (Llama-3) │ │ Wallet │ │ │ └──────┬───────┘ └──────┬───────┘ └──────┬───────┘ │ │ │ │ │ │ │ ┌──────▼──────────────────▼──────────────────▼───────┐ │ │ │ Privacy & Shielding Engine │ │ │ │ • Zcash Sapling Pools • Halo2 Proofs │ │ │ │ • zk-DNS Resolution • No Telemetry │ │ │ └──────────────────────┬──────────────────────────────┘ │ │ │ │ │ ┌──────────────────────▼──────────────────────────────┐ │ │ │ Tor Expert Bundle │ │ │ │ • Onion Routing • Exit Node Rotation │ │ │ └──────────────────────┬──────────────────────────────┘ │ └─────────────────────────┼──────────────────────────────┘ │ ▼ Encrypted Internet ``` *** ## 🛡️ Layer 1: Zero-Knowledge Proofs ### What Are Zero-Knowledge Proofs? **Zero-knowledge proofs** let you prove something is true without revealing WHY it's true. **Example:** * **Traditional:** "I'm over 21" → Show full birthday, ID, name, address * **Zero-knowledge:** "I'm over 21" → Mathematical proof (reveals nothing else) ### How zer0 Uses ZK-Proofs #### 1. Shielded Transactions (Zcash Sapling) All $zer0 token transactions are fully private: ``` Traditional Crypto: Alice → 5 $zer0 → Bob (Everyone sees: sender, receiver, amount) zer0 with zk-Proofs: Shielded Pool Activity Detected (Nobody sees: who, what, how much) ``` **Technical Implementation:** * **Sapling Protocol** - zkSNARK-based shielded addresses * **Note Commitments** - Encrypted transaction details * **Nullifiers** - Prevent double-spending without revealing sender #### 2. Anonymous Browsing Proofs (Halo2) Prove you're human without revealing identity: ``` Challenge: "Prove you're not a bot" Traditional: CAPTCHA (trains AI, wastes time, tracks device) zer0 zk-Proof: Submit proof of computational work → Website knows you're human → You revealed zero information ``` **Use Cases:** * Anti-bot protection without tracking * Age verification without ID * Payment proof without transaction details * Reputation without identity #### 3. zk-Cohort Advertising Advertisers target WITHOUT personal data: ``` Traditional Ads: "John Smith, 34, NYC, $120k salary, likes crypto" → Invasive, creepy, data breach risk zer0 zk-Ads: "User in cohort #482: [Crypto enthusiast, 25-40, Urban]" → Effective targeting, zero PII → 10x better CPM ($50 vs $5) ``` **How It Works:** 1. Your device generates anonymous cohort proof 2. Ad network sees: "Cohort 482 viewed site X" 3. Bidders compete: "I'll pay $50 CPM for cohort 482" 4. You earn $zer0, advertiser gets results, privacy intact *** ## 🧅 Layer 2: Tor Network Integration ### What is Tor? **Tor (The Onion Router)** bounces your traffic through 3+ random servers worldwide, making it impossible to trace. ``` You → Guard Node → Middle Node → Exit Node → Website 🔒 🔒 🔒 🔓 Each node only knows its neighbors - no one sees the full path ``` ### zer0's Tor Implementation #### Built-In Tor Expert Bundle **Traditional Tor Browser:** * Separate application * Limited compatibility * Slow and clunky * Not a daily driver **zer0's Integration:** * Embedded in browser * Full Chromium compatibility * Optimized routing * Seamless experience #### Enhanced Tor Features | Feature | Standard Tor | zer0 Tor | | ----------------------- | -------------- | ---------------------------------- | | **Circuit Building** | 3 hops, random | 3-5 hops, optimized for speed | | **Exit Node Selection** | Random | Smart (geographic preferences) | | **Bridge Support** | Manual setup | Auto-enabled in blocked regions | | **Circuit Rotation** | Every 10 min | Configurable (per-site, manual) | | **Performance** | Baseline | 20-30% faster (route optimization) | #### zk-DNS: Private DNS Resolution **The Problem:** Even with Tor, DNS queries can leak your browsing: ``` Regular DNS: You → ISP DNS → "Looking up zer0.build" ISP now knows you visited zer0.build ``` **zer0's Solution:** ``` zk-DNS: You → Tor → zk-DNS Resolver → Encrypted Response Nobody knows what sites you're visiting ``` **Features:** * DNS-over-HTTPS (DoH) via Tor * Multiple resolver fallbacks * DNSSEC validation * Zero logging *** ## 💻 Layer 3: On-Device Computation ### Why On-Device Matters **Cloud AI Services (ChatGPT, Claude, etc.):** ``` You: "Analyze my financial spreadsheet" ↓ [Data uploaded to cloud] ↓ AI Company: Now has your financial data Government: Can subpoena the data Hackers: Can breach the servers ``` **zer0 On-Device AI:** ``` You: "Analyze my financial spreadsheet" ↓ [Llama-3-8B processes locally] ↓ Result: Insights generated Nobody else saw your data - not even us ``` ### Local AI Stack #### Model Architecture **Llama-3-8B Optimized** * **Size:** 4-8 GB compressed * **Speed:** 20-50 tokens/sec on consumer CPU * **Accuracy:** GPT-3.5 equivalent for most tasks * **Privacy:** 100% local, zero cloud calls **Optimization Techniques:** * **Quantization:** INT4/INT8 for 4x faster inference * **KV Cache:** Reuse computations across requests * **Batching:** Process multiple requests efficiently * **WebGPU:** GPU acceleration when available #### Agent Sandboxing Each agent runs in isolated sandbox: ``` ┌─────────────────────────────────────┐ │ Agent Sandbox │ │ │ │ ┌─────────────────────────────┐ │ │ │ AI Model Execution │ │ │ │ (Read-only file access) │ │ │ └─────────────────────────────┘ │ │ │ │ ┌─────────────────────────────┐ │ │ │ Memory Isolation │ │ │ │ (No data persistence) │ │ │ └─────────────────────────────┘ │ │ │ │ ┌─────────────────────────────┐ │ │ │ Network Restrictions │ │ │ │ (Tor-only, whitelisted) │ │ │ └─────────────────────────────┘ │ └─────────────────────────────────────┘ ``` **Security Benefits:** * Agents can't exfiltrate data * Crashed agents don't affect browser * Malicious agents can't access wallet * Complete audit trail of agent actions *** ## 🔒 Additional Privacy Features ### 1. Always-On Incognito Mode **Cannot be disabled** - this is zer0's core promise: * ✅ No browsing history saved * ✅ No cookies persist across sessions * ✅ No cache survives browser restart * ✅ No form data remembered * ✅ No download history logged ### 2. WebRTC Leak Prevention WebRTC can expose your real IP even through VPN/Tor: ``` Vulnerable Browser: Tor says IP: 185.220.101.34 (Germany) WebRTC leaks: 192.168.1.100 (Your real local IP) → Privacy broken ``` **zer0's Protection:** * WebRTC disabled by default * Strict ICE candidate filtering * Real IP never exposed ### 3. Browser Fingerprinting Protection Websites track you via browser "fingerprint": **Fingerprint Components:** * Screen resolution * Installed fonts * Canvas rendering * WebGL capabilities * Audio context * Installed plugins * Timezone * Language settings **zer0's Countermeasures:** * Randomize non-critical values * Normalize revealing attributes * Block advanced fingerprinting APIs * Regular fingerprint rotation **Result:** Your fingerprint changes every session, making tracking impossible. ### 4. Cookie & Tracker Blocking **Built-in blocking (no extensions needed):** | Type | Default Action | Customizable | | ----------------------- | -------------- | ------------ | | **Third-party cookies** | ❌ Blocked | ✅ | | **Third-party scripts** | ❌ Blocked | ✅ | | **Tracking pixels** | ❌ Blocked | ❌ | | **Crypto miners** | ❌ Blocked | ❌ | | **Malware domains** | ❌ Blocked | ❌ | ### 5. HTTPS Everywhere * Auto-upgrade HTTP → HTTPS * Warn on insecure connections * Block mixed content * HSTS preload list included *** ## 🔐 Cryptographic Primitives ### Encryption Standards **Transport Layer:** * TLS 1.3 minimum * Perfect Forward Secrecy (PFS) * Strong cipher suites only **Storage Layer:** * AES-256-GCM for wallet encryption * Argon2id for password hashing * Secure key derivation (BIP-39) ### Random Number Generation **Critical for:** * Wallet seed phrases * zk-Proof generation * Tor circuit selection **Source:** * OS-level CSPRNG (/dev/urandom, CryptGenRandom) * Hardware RNG when available (TPM, Secure Enclave) * Entropy pooling from user interactions *** ## 🛡️ Threat Model ### What zer0 Protects Against | Threat | Protection Level | Notes | | ---------------------------- | ---------------- | --------------------------------------------- | | **Passive ISP Surveillance** | 🟢 Complete | Tor hides all traffic content | | **Active ISP Inspection** | 🟢 Complete | zk-DNS prevents DNS leaks | | **Website Tracking** | 🟢 Complete | No cookies, fingerprint protection | | **Advertiser Tracking** | 🟢 Complete | zk-cohorts instead of personal data | | **Government Surveillance** | 🟢 Strong | No logs, zk-proofs, Tor routing | | **Malware** | 🟡 Good | Sandboxing, but user discretion needed | | **Phishing** | 🟡 Basic | Warnings, but user vigilance required | | **Physical Device Access** | 🟡 Limited | Encryption at rest, but unlocked = vulnerable | ### What zer0 Cannot Protect Against **Be aware of these limitations:** 1. **Compromised Exit Nodes** * Tor exit nodes can see unencrypted (HTTP) traffic * **Mitigation:** Always use HTTPS (zer0 enforces this) 2. **JavaScript-Based Attacks** * Malicious JS can still execute (needed for modern web) * **Mitigation:** Disable JS for high-security browsing 3. **Browser Exploits** * Zero-day vulnerabilities in Chromium * **Mitigation:** Keep zer0 updated, bug bounty program 4. **Social Engineering** * Phishing, fake sites, user error * **Mitigation:** User education, built-in warnings 5. **Physical Access** * Someone with your device can access everything * **Mitigation:** Strong password, encrypt device, never leave unlocked *** ## 📊 Privacy Metrics & Audits ### Verified Privacy Claims | Metric | Value | Verified By | | ----------------------- | ---------- | --------------------- | | **Telemetry Sent** | 0 bytes | Open-source auditable | | **IP Leaks (WebRTC)** | 0 detected | ipleak.net tests | | **DNS Leaks** | 0 detected | dnsleaktest.com | | **Fingerprint Entropy** | 15.2 bits | amiunique.org | | **Tracker Blocking** | 99.8% | EFF Cover Your Tracks | ### Third-Party Audits **Security Audits:** * 🟢 **Trail of Bits** (Q1 2026) - Comprehensive security review * 🟢 **Least Authority** (Q2 2026) - Zcash integration audit * 🔄 **Ongoing Bug Bounty** - $500k pool, HackerOne platform **Privacy Audits:** * 🟢 **Cure53** - Browser privacy assessment * 🟢 **NCC Group** - Cryptographic implementation review *** ## 🔬 Technical Deep Dives Want to learn more about specific technologies?
Zero-Knowledge ProofsTechnical details on zk-SNARKs and Halo2https://github.com/Onesignature/Zer0-gitbook/blob/main/technical-documentation/zero-knowledge-proofs.md
Technology StackComplete tech stack breakdownhttps://github.com/Onesignature/Zer0-gitbook/blob/main/technical-documentation/technology-stack.md
Security AuditsFull audit reports and findingshttps://github.com/Onesignature/Zer0-gitbook/blob/main/technical-documentation/security.md
*** {% hint style="success" %} **zer0's privacy architecture is open-source and auditable.** Don't trust, verify! Check our [GitHub](https://github.com/BrowserZer0/Zer0) to see every line of code. 🔍 {% endhint %} --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.zer0.build/core-concepts/privacy-architecture.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.