Censors and Cypherpunks at War: In India's evolving internet landscape, the state's censorship apparatus is growing in sophistication – from old-school DNS blocks to modern SNI-based filtering and deep packet inspection (DPI). But so too are the tools of resistance. This article explores how internet censorship is implemented in India and how obfuscation technologies like obfs4, Shadowsocks, and V2Ray act as countermeasures.
How India Censors the Web: Techniques and Telltale Signs
India's internet censorship has legal backing in Section 69A of the IT Act (2000), which allows the government to order blocking of content in the interest of national security, public order, etc. However, the implementation of these orders is largely opaque – companies and ISPs are gagged from revealing blocking requests, and users often get no explanation beyond a generic error.
Technically, Indian ISPs historically relied on blunt methods like DNS blocking and HTTP redirection to implement censorship. In recent years, they have adopted more nuanced (though still not foolproof) approaches:
DNS Filtering/Spoofing
Some ISPs simply tamper with DNS responses for blacklisted domains. When you try to visit a blocked site, the ISP's DNS resolver might return a wrong IP address or no address at all, effectively making the site unreachable. State-run providers like BSNL and MTNL have been observed returning incorrect IPs for blocked sites. This method is easy to implement but also easy to bypass.
HTTP Blocking and Injection
For unencrypted HTTP traffic, ISPs often use middleboxes that scan for blocked domain names or URLs in the plaintext requests. If a user tries to access a banned URL over HTTP, the ISP can reset the connection or redirect them to a block notice page. In India, HTTP-based blocking is the most common technique, observed in 64 out of 71 networks tested in a recent study.
SNI-Based TLS Blocking
The move to HTTPS across the web posed a challenge to censors because the content of requests is encrypted. However, one piece of information in an HTTPS handshake often remains in plaintext: the Server Name Indication (SNI), which reveals the hostname the user is trying to reach. Indian ISPs have seized on this. Research by the Centre for Internet & Society (CIS) and OONI confirmed that major ISPs like Bharti Airtel and Reliance Jio now use SNI inspection to block HTTPS websites.
Bypassing Censorship: Obfuscation Tools in Action
For every censorship technique, there's a countermeasure. Indian users have several tools at their disposal to reclaim access to information:
Alternate DNS and DoH/DoT
The simplest fix for DNS blocking is to change your DNS server. If your ISP's DNS lies to you, services like Google DNS or Cloudflare DNS (1.1.1.1) will give you the real address. Better yet, use DNS over HTTPS (DoH) or DNS over TLS (DoT), which encrypt DNS queries so your ISP cannot sniff or tamper with them easily.
VPNs and Proxy Tunnels
A VPN (Virtual Private Network) creates an encrypted tunnel between your device and a server outside India. To your ISP, it looks like you're just exchanging data with one server, not what site or service you're ultimately accessing. VPNs can easily bypass DNS, HTTP, and SNI blocks because the ISP can't see the actual website you're visiting – only the VPN server's IP.
Tor with obfs4
The Tor network is a stalwart tool for censorship circumvention. Standard Tor traffic has a recognizable fingerprint, so censors like China's Great Firewall block the public Tor relays. The solution: pluggable transports like obfs4 which transform Tor traffic to look random and innocuous.
Shadowsocks and V2Ray
Originating from Chinese developers, Shadowsocks is often described as a "secure SOCKS5 proxy". It's designed to be hard to detect: it uses techniques like randomizing packet sizes and timings. V2Ray is a newer platform that supports multiple proxy protocols and built-in obfuscation. It's popular in China and Iran for its flexibility – you can run it over TCP, WebSocket, gRPC, and even camouflage as normal HTTPS traffic.
India vs. Iran, China, Russia: A Contrast in Censorship
Compared to the Great Firewall of China, India's censorship is less pervasive and technologically less aggressive – at least for now. China operates a national firewall that not only blocks thousands of domains but also scans and filters traffic for undesirable content or tools.
Iran, especially during periods of protest, has shown a willingness to almost shut off the regular internet, whitelisting only certain services. Iran's national intranet, the "National Information Network," can isolate the country from the outside.
Russia has been ramping up its censorship under the "Sovereign Internet" initiative. They've deployed DPI boxes to ISPs that can filter content. In 2021, Russia famously throttled Twitter's bandwidth as a warning shot, by identifying traffic to Twitter's domains and slowing it down to a crawl.
The Cypherpunk's Response: Stay Tactically Ahead
For privacy and freedom advocates in India, the answer to growing censorship is to stay a step ahead with tactics and technology. This is the ethos that drives netsec.gg as a tactical tech collective: empower users with tools and knowledge so that they can reclaim their rights online.
In conclusion, internet censorship in India is growing but still highly defeatable with the right tactics. Obfuscation techniques – from the humble DNS tweak to advanced tools like obfs4 and V2Ray – give users the upper hand, at least for now. The situation remains dynamic: if censors escalate (with nationwide DPI or legal bans on tools), the circumvention community will need to innovate further. This tug-of-war is exactly what the cypherpunk ethos prepares us for: it's a marathon of technical creativity in defense of civil liberties.