libsodium

Libsodium is a software library that handles cryptographic operations, meaning things like encrypting data so only the intended recipient can read it, verifying that a piece of data has not been tampered with, creating digital signatures, and storing passwords securely. It is written in C and is used by developers who need to add security features to their applications without having to understand the deep mathematical details of cryptography themselves.

The library is designed to work on a wide range of platforms: Windows (both 32-bit and 64-bit, as well as ARM), iOS, Android, and even in web browsers via WebAssembly and JavaScript. This makes it useful for projects that need to run in many different environments.

Libsodium started as a fork of NaCl (a well-regarded cryptography library), and it maintains compatibility with NaCl while adding features that make it easier to install and package. The goal has always been to keep the interface straightforward so developers make fewer security mistakes.

The project follows a two-tier release schedule. Regular point releases add new features or significant changes. Between those, stable releases handle small bug fixes and maintenance without breaking anything or adding new behavior. Security patches go to the stable branch right away.

The library is free to use under the ISC license, which is a short, permissive open-source license. If you are a developer building an app that needs to encrypt data or verify identities, libsodium is a widely trusted option with thorough documentation available at doc.libsodium.org.