Habr•October 10, 2026•🇷🇺Translated from Russian

Privacy-Focused Browser Tool Compresses PDFs Locally Without Uploading Sensitive Documents

A developer frustrated with online PDF compression services has released a browser-based tool that processes files entirely on the user’s device, eliminating the need to upload sensitive documents such as birth certificates, diplomas, and financial reports.

The project began when a multi-page PDF containing scans of passport data and official documents had to meet a strict one-megabyte limit for an embassy submission. Standard search results pointed to free online compressors, yet the author rejected them because the files represented a complete identity package that could enable impersonation if mishandled.

Desktop alternatives such as Ghostscript, Apple’s Preview, and paid editors were available on a personal laptop, but the same constraints appeared later on other computers and especially on mobile phones. Presentations containing financial figures, internal reports, and contracts repeatedly exceeded email or portal limits, leaving users with the choice of installing command-line tools or sending data to unknown servers.

The resulting web application, designed with mobile use as the primary scenario, opens in Safari or Chrome, can be added to the home screen, and continues working without an internet connection after the initial visit. On phones it avoids memory-related tab reloads by capping images at four megapixels, which remains sufficient for legible A4 output.

Performance tests show size reductions between 66 and 97 percent on scanned and photographic content. On purely textual PDFs the tool underperforms Ghostscript and explicitly informs users of this limitation. No files ever leave the device, addressing the core privacy concern that originally motivated the project.

Related articles

Habr•Privacy & Surveillance

Building Prizrak: How a Developer Created a Federated Messenger That Masks All Traffic as Legitimate HTTPS

A developer created Prizrak, a federated messenger with end-to-end encryption where all traffic, including calls, is indistinguishable from ordinary HTTPS connections. The project addresses three common limitations of existing messengers: centralized control points, mandatory phone numbers, and detectable encrypted traffic. It uses real TLS 1.3 handshakes to actual domains, multi-port listening, and a hidden token mechanism inside the encrypted channel. When servers cannot reach each other directly, messages are delivered through a network of storage nodes modeled after Ceph's RADOS system. Voice and video calls run on a native media stack with custom STUN-like functionality and careful UDP buffer sizing to avoid packet truncation. An integrated two-hop VPN reuses the same stealth transport while keeping messenger traffic outside the tunnel.

Habr•Privacy & Surveillance

GrapheneOS Setup Guide: Configuring Pixel Phones for Corporate Surveillance-Free Daily Use

This comprehensive engineering guide explains how to deploy GrapheneOS on supported Google Pixel devices to eliminate corporate telemetry collection. It follows three core principles: rejecting proprietary ecosystems, applying Zero Trust through cryptography and open-source audits, and enforcing strict compartmentalization via isolated user profiles. The tutorial covers official installation via the Web Installer, basic owner profile hardening with PIN shuffling and automatic reboot, and the use of Obtainium for direct FOSS app management from GitHub repositories. Detailed recommendations include privacy-focused tools such as KeePassDX, Aegis Authenticator, AmneziaVPN, Signal, and Fossify applications, along with VPN kill-switch configuration. Regional profiles are created for sandboxed Google Play, Aurora Store, RuStore, and Huawei AppGallery to safely run banking, marketplace, and social apps without cross-profile tracking.

Habr•Privacy & Surveillance

Following the White Rabbit: Developer Builds Custom Rust VPN PAYPHONE Using QUIC and Obfuscation to Evade Detection

A Russian developer has released PAYPHONE, an experimental IPv4 VPN written entirely in Rust that uses QUIC datagrams and optional TLS-over-TCP transport with custom obfuscation. The project aims to provide an alternative to AmneziaWG and Xray/VLESS+REALITY stacks that are commonly used to bypass Russian internet filtering. The article details the full packet path from TUN interface through a 16-byte PAYPHONE header, session management with Ed25519 tokens, and multiple post-launch bugs including MTU miscalculations, self-routing loops on macOS, and timer lifetime issues in Tokio. Key technical choices include RFC 9221 datagram support to avoid head-of-line blocking for multiplexed TCP flows and token-bucket rate limiting tied to subscription tokens. The author also describes route monitoring every 400 ms and interface-bound sockets to prevent the tunnel from swallowing its own control traffic.

AntiMalware•Privacy & Surveillance

WhatsApp Introduces Parental Controls for Teen Privacy Settings

WhatsApp, owned by Meta (recognized as an extremist organization and banned in Russia), has rolled out new parental control tools for family accounts. Parents can manage privacy settings, group participation, channel access, status visibility, and Meta AI usage for teens, but cannot read personal messages due to end-to-end encryption. All controls are voluntary and require joint setup with the teenager, protected by a single PIN code that prevents easy reversal of restrictions. Notifications alert parents when teens join or leave groups or when group sizes change significantly. Separate options cover channel usage, viewable statuses, and audience controls for teen posts. Meta AI access can be set to a standard 13+ mode or a stricter Limited Content mode with undisclosed restrictions. The company plans to expand these features gradually based on family feedback while maintaining encryption protections.