Ecosystem · Libraries

libsodium

libsodium is the modern, opinionated crypto library by Frank Denis. It descends from Daniel J. Bernstein’s NaCl (“networking and cryptography library”) and adds portability, packaging, and a clean API surface. The headline feature is the absence of choice: each primitive is one carefully-picked algorithm with sensible defaults.

What it picks for you

API	Underlying algorithm
`crypto_generichash`	BLAKE2b
`crypto_pwhash`	Argon2id
`crypto_shorthash`	SipHash-2-4
`crypto_kdf`	HKDF-SHA-512
`crypto_auth`	HMAC-SHA-512/256
`crypto_sign`	Ed25519 (uses SHA-512 internally)
`crypto_box`	X25519 + XSalsa20-Poly1305

Why the opinionated style works

No misuse opportunities, no nonce mode mistake, no IV confusion, no “raw SHA-256 of a key” footgun.
Bindings everywhere , Python (pynacl), Node (sodium-native), Rust (sodiumoxide / dryoc), Go (gocrypt), PHP (built-in since 7.2), Erlang, Haskell, R, you name it.
Strong defaults , the moderate / sensitive / interactive presets for password hashing match modern recommendations.
Cross-platform , runs on Linux, macOS, Windows, iOS, Android, WebAssembly, microcontrollers.

A small example

#include <sodium.h>

unsigned char hash[crypto_generichash_BYTES];
crypto_generichash(hash, sizeof hash,
                   data, data_len,
                   NULL, 0);                   // unkeyed
crypto_generichash(hash, sizeof hash,
                   data, data_len,
                   key, sizeof key);           // keyed (MAC)

// Password hash
char hashed[crypto_pwhash_STRBYTES];
crypto_pwhash_str(hashed, password, password_len,
                  crypto_pwhash_OPSLIMIT_MODERATE,
                  crypto_pwhash_MEMLIMIT_MODERATE);

Where it is deployed

Tox, Signal-adjacent messengers.
Tor onion service v3 internals (with libsodium as a dependency).
Bitcoin Core test infrastructure.
Magic Wormhole (file transfer over PAKE).
Many indie / open-source projects that did not want to wire up OpenSSL.

HACL*, when you want proofs

If you need formally-verified hashing code (proved correct in F*), the canonical project is HACL* / EverCrypt. Mozilla’s NSS integrates HACL* primitives for performance-critical paths.