Picocrypt

Picocrypt is a small, portable, and open-source file encryption tool designed to provide high-level security with extreme simplicity. It is often cited alongside veteran tools like VeraCrypt as a top-tier choice for secure data protection .

The program is a single, statically-linked executable ( .exe on Windows, .AppImage on Linux, or a .dmg on macOS). There’s no installer, no registry changes, no dependencies to install, and no internet access—ever. You download it, double-click it, and it works. picocrypt

The entire source code (written in Go) is ~2,000 lines. A single developer (Evan Su) maintains it, and the code is written to be read by humans, not just compilers. This means security researchers can fully audit the program in an afternoon—not a year. Picocrypt is a small, portable, and open-source file

The name derives from the metric prefix for one-trillionth (10⁻¹²), signifying smallness . The entire program is roughly . To put that in perspective, that’s smaller than most high-resolution JPEG photos. It consumes minimal RAM and CPU cycles, making it ideal for old hardware, live USBs, or air-gapped machines. There’s no installer, no registry changes, no dependencies

The core of Picocrypt’s security model lies in its use of the XChaCha20-Poly1305 authenticated encryption algorithm. This choice distinguishes it from older tools that rely on AES in modes that can be susceptible to padding oracle attacks if implemented incorrectly. XChaCha20 is a stream cipher renowned for its speed and high security margin, widely adopted by modern protocols like WireGuard and TLS. Furthermore, by employing Poly1305 for authentication, Picocrypt ensures not only confidentiality (preventing unauthorized viewing) but also integrity (ensuring the file has not been tampered with). This is a critical feature often overlooked in simpler tools; without authentication, an attacker could modify an encrypted file without knowing the key, potentially corrupting data or introducing vulnerabilities upon decryption.