BTC21 / Explorer / Privacy Policy

Zero Tracking No Cookies Cypherpunk Ethos Tor Peering

Privacy Policy & Cypherpunk Data Manifesto

BTC21 operates under strict Bitcoin maximalist, cypherpunk, and libertarian privacy principles. We do not track you, we do not set cookies, we do not profile your behavior, and we never monetize your data. Below is our transparent disclosure of how this public server handles network interactions.

Published: September 1, 2026 · Effective: Immediately · Applies to explorer.btc21.cc and btc21.cc

Our Privacy Pledge: Zero-Surveillance Architecture

🚫 No Tracking Analytics

No Google Analytics, Meta pixels, telemetry beacons, or third-party monitoring scripts.

🍪 Zero HTTP Cookies

We set zero tracking cookies, session identifiers, or persistent browser storage tokens.

👤 No Accounts or PII

No user registration, email capture, passwords, KYC/AML documents, or personal data.

💰 Never Sold or Monetized

We collect no commercial data and will never sell, rent, or share user information.

⚡ Defensive Logs Only

Volatile IP connection logs exist solely for Fail2ban firewall defense against hackers & DDoS.

🧅 Native Tor v3 Support

Onion routing supported for private, location-hidden Bitcoin Core P2P peer connections.

"Privacy is necessary for an open society in the electronic age. Privacy is not secrecy. A private matter is something one doesn't want the whole world to know, but a secret matter is something one doesn't want anybody to know. Privacy is the power to selectively reveal oneself to the world."

— Eric Hughes, A Cypherpunk's Manifesto (1993)

Section 01

Cypherpunk & Libertarian Privacy Ethos

BTC21 was built as an act of service to the Bitcoin network and the principles of individual sovereignty. In the modern web, surveillance capitalism has become ubiquitous: websites track users across the internet, harvest telemetry, sell browsing habits to advertising brokers, and build behavioral profiles.

We categorically reject this model. You are not a product, and your interactions with a public Bitcoin node should not be monitored. We believe that financial privacy, unencumbered speech, and freedom of association are foundational human rights. Our infrastructure is intentionally engineered to minimize data retention, eliminate tracking vectors, and respect the autonomy of every visitor.

Section 02

Zero-Surveillance Architecture: What We NEVER Collect or Do

We believe that the most effective way to protect user data is to never collect it in the first place. The following table provides an unambiguous breakdown of surveillance mechanisms commonly used across the web and our strict policy against them:

Technology / Practice	BTC21 Status	Details
Third-Party Analytics	NONE	No Google Analytics, Cloudflare telemetry, Mixpanel, Matomo, or tracking scripts.
Tracking Pixels & Beacons	NONE	No Meta/Facebook pixels, X/Twitter conversion tags, or ad network beacons.
HTTP Cookies	NONE	Zero cookies are set, read, or required. No session, persistent, or auth cookies.
Device Fingerprinting	NONE	No canvas hashing, WebGL profiling, audio probing, or device telemetry scripts.
Personal Accounts / PII	NONE	No user registration, email forms, passwords, phone numbers, or identity checks.
Data Selling or Monetization	NONE	We will never sell, rent, monetize, broker, or transfer any user data to anyone.

You can inspect our pages using your browser's Developer Tools (Network and Application tabs) at any time to verify that zero external tracking requests or cookies are ever dispatched.

Section 03

What Minimal Operational Data Is Processed & Why (Defensive Security)

We believe in total technical honesty. In order to transmit data over the internet, computers must process network packets. Below is an exact accounting of what technical data is processed, how it is used, and how it is protected:

Ephemeral TCP/IP Connection Data

When your web browser or script sends an HTTP/HTTPS request to explorer.btc21.cc or btc21.cc over clearnet, our Linux kernel and Nginx web server receive standard TCP/IP packet headers. This includes your IP address, requested URL, user agent string, and timestamp.

Why this data is processed (Strictly Defensive Purposes):

Data Transmission: To route the requested HTML, CSS, block details, or API response back to your client device.
DDoS & Flood Mitigation: To protect our bare-metal hardware, system memory, and network connection from volumetric Denial-of-Service attacks.
Automated Fail2ban Intrusion Defense: We run automated Fail2ban security filters that monitor server error and access logs in real-time. If an IP address repeatedly executes brute-force exploit attempts, scans for vulnerabilities, floods API endpoints, or attempts malicious attacks, Fail2ban dynamically drops and bans that IP address at the Linux kernel firewall level (iptables/nftables).
Rate Limiting: To enforce fair usage policies so no automated bot can monopolize node capacity or disrupt service for the broader community.

Log Retention and Hygiene: Web server logs are stored locally on the dedicated server with strict root-only permissions. Logs are automatically rotated, compressed, truncated, and deleted on a routine schedule. We do NOT maintain historical user dossiers, and we do NOT correlate IP addresses with queried Bitcoin transactions or addresses.

Section 04

Public Blockchain Architecture vs. Web Privacy

It is vital for all users to understand the distinction between web server privacy and the nature of the Bitcoin protocol:

Bitcoin is a Public Ledger: Every Bitcoin block, transaction, input, output, and satoshi value broadcast to the network is publicly recorded on thousands of archival nodes globally forever. Nothing on the Bitcoin blockchain is private from the network itself.
Local Index Lookups: When you search for a transaction hash (TXID), block height, or Bitcoin address on explorer.btc21.cc, the query is processed internally against our local Bitcoin Core archival node and Electrs index. BTC21 does NOT store an index linking your IP address to the Bitcoin addresses you search.
Clearnet ISP Visibility: If you browse the explorer over the standard clearnet internet without an encrypted tunnel (such as Tor or a VPN), your Internet Service Provider (ISP), network administrator, or intermediate routing hops can observe that your IP address visited explorer.btc21.cc.

Privacy Recommendation: If you are looking up your personal Bitcoin addresses or transactions and wish to prevent third parties on your local network or ISP from knowing you are using this explorer, use Tor Browser or a trusted, no-log privacy VPN (e.g. Mullvad).

Section 05

Maximizing Your Privacy: Tor Peering, VPNs & Sovereign Nodes

As Bitcoin maximalists and privacy advocates, we actively encourage and provide tools to maximize your operational security:

Tor v3 Onion Peering: BTC21 maintains a permanent Tor v3 hidden service for private, location-hidden Bitcoin Core P2P peering:
2hi75kbrmaeldlevhusf5j7rh2ts672bdw7ikhnmv5oe34o7fhfdxtad.onion:8333
Peers connecting over this address do not reveal their clearnet IP addresses to BTC21 or network transit providers.
BIP324 P2P Encryption: BTC21 has BIP324 (v2 P2P transport) enabled, providing end-to-end encrypted communications between compatible Bitcoin Core peers to defeat passive network eavesdropping.
BIP157/158 Compact Block Filters: BTC21 serves compact block filters, allowing lightweight client wallets to determine whether a block contains relevant transactions without disclosing their wallet addresses to our node.
Run Your Own Sovereign Node: The cypherpunk motto is "Don't trust, verify." While BTC21 is honored to provide this public community resource, the ultimate privacy and financial sovereignty comes from running your own Bitcoin Core node at home (on hardware such as a Raspberry Pi, Start9, Umbrel, or standard PC). We encourage everyone to run their own node!

Section 06

Hardware & Bare-Metal Infrastructure Security

Many public services are hosted on commoditized third-party virtual private servers (VPS) or cloud platforms where virtual machine hypervisors and hosting providers can inspect server memory and network streams.

BTC21 is deployed on dedicated, bare-metal physical hardware situated in an enterprise data center. We do not use third-party reverse proxies or cloud CDNs that terminate TLS or decrypt user traffic. The operating environment utilizes hardened Linux kernel security, minimal exposed attack surfaces, disabled remote Bitcoin Core RPC exposure, isolated non-root system users, and encrypted SSL/TLS endpoints.

Section 07

Third-Party Links & External Resources

The Service may contain hyperlinks to independent third-party websites, documentation, or open-source repositories (such as Bitcoin.org, GitHub, or upstream software tools). We have no ownership, control, or supervision over the privacy policies, data practices, or content of third-party platforms. Clicking external links is governed solely by the privacy statements of those respective destinations.

Section 08

Policy Modifications & Updates

We may update or refine this Privacy Policy periodically to reflect technical infrastructure improvements or operational updates. Any revisions will be published directly to this URL (https://explorer.btc21.cc/privacy.html). Because we collect no email addresses or contact details, we cannot send direct notifications. We invite you to review this page periodically to verify our ongoing commitment to zero tracking.

Section 09

Community Verification & Contact

BTC21 is a voluntary community project funded and operated independently for the benefit of the Bitcoin network. We welcome scrutiny, verification, and constructive feedback from fellow node runners, developers, and cypherpunks.

If you discover a security vulnerability or have questions regarding our privacy architecture, please review our public node documentation or reach out via our community channels.