libsodium Cryptography Library

libsodium is a modern, easy-to-use software library for encryption, decryption, signatures, password hashing and more, serving as a portable, cross-compatible and simplified fork of NaCl (Networking and Cryptography library) originally created by Daniel J. Bernstein. Key features: modern cryptography primitives including authenticated encryption (secretbox using XSalsa20-Poly1305, AEAD using ChaCha20-Poly1305 and XChaCha20-Poly1305). Public-key cryptography with Box (curve25519 Diffie-Hellman), Sign (Ed25519 digital signatures), and Sealed Boxes for anonymous sender encryption. Hashing with BLAKE2b and SHA-256. Password hashing via Argon2id, scrypt, and pwhash with tunable memory and CPU parameters for resistance against GPU and ASIC attacks. Key derivation via HKDF and BLAKE2b-based KDF for deriving multiple keys from a single master key. Secret-key authentication with HMAC-SHA256 and Poly1305 MAC. Random number generation with cryptographically secure cross-platform entropy sources. Constant-time comparisons and memory-guarded operations to prevent side-channel attacks. Easy-to-use API with sensible defaults that prevent common cryptographic mistakes. Cross-platform on Windows, macOS, Linux, Android, iOS, and WebAssembly. Bindings available for Python, Ruby, PHP, Rust, Go, Java, JavaScript, and 40+ languages. Used by Signal, WireGuard, Minisign, and countless security-focused applications.