libsodium

What is libsodium?

libsodium is a modern, easy-to-use software library for encryption, decryption, signatures, password hashing, and more. It is designed to be a portable, cross-compilable, installable, and packageable fork of NaCl, with a compatible API.

What are libsodium's main functionalities?

Public Key Cryptography

This feature allows you to perform public key cryptography operations such as encryption and decryption. The code sample demonstrates generating a key pair, encrypting a message, and logging the ciphertext and nonce.

const sodium = require('libsodium-wrappers');
(async() => {
  await sodium.ready;
  const keyPair = sodium.crypto_box_keypair();
  const message = 'Hello, World!';
  const nonce = sodium.randombytes_buf(sodium.crypto_box_NONCEBYTES);
  const cipherText = sodium.crypto_box_easy(message, nonce, keyPair.publicKey, keyPair.privateKey);
  console.log({ cipherText, nonce });
})();

Secret Key Cryptography

This feature allows you to perform secret key cryptography operations such as encryption and decryption. The code sample demonstrates generating a key, encrypting a message, and logging the ciphertext and nonce.

const sodium = require('libsodium-wrappers');
(async() => {
  await sodium.ready;
  const key = sodium.randombytes_buf(sodium.crypto_secretbox_KEYBYTES);
  const nonce = sodium.randombytes_buf(sodium.crypto_secretbox_NONCEBYTES);
  const message = 'Hello, World!';
  const cipherText = sodium.crypto_secretbox_easy(message, nonce, key);
  console.log({ cipherText, nonce });
})();

Password Hashing

This feature allows you to hash passwords securely. The code sample demonstrates hashing a password and logging the hashed password.

const sodium = require('libsodium-wrappers');
(async() => {
  await sodium.ready;
  const password = 'mysecretpassword';
  const hashedPassword = sodium.crypto_pwhash_str(password, sodium.crypto_pwhash_OPSLIMIT_INTERACTIVE, sodium.crypto_pwhash_MEMLIMIT_INTERACTIVE);
  console.log({ hashedPassword });
})();

Digital Signatures

This feature allows you to create and verify digital signatures. The code sample demonstrates generating a key pair, signing a message, and logging the signed message.

const sodium = require('libsodium-wrappers');
(async() => {
  await sodium.ready;
  const keyPair = sodium.crypto_sign_keypair();
  const message = 'Hello, World!';
  const signedMessage = sodium.crypto_sign(message, keyPair.privateKey);
  console.log({ signedMessage });
})();

Other packages similar to libsodium

crypto

The 'crypto' module in Node.js provides cryptographic functionality that includes a set of wrappers for OpenSSL's hash, HMAC, cipher, decipher, sign, and verify functions. It is built into Node.js and does not require additional installation. While it offers a wide range of cryptographic operations, it may not be as user-friendly or modern as libsodium.

tweetnacl

TweetNaCl is a cryptographic library that is a port of the Networking and Cryptography library (NaCl) to JavaScript. It is designed to be small, fast, and easy to use. While it offers similar functionalities to libsodium, it may lack some of the advanced features and optimizations found in libsodium.

bcrypt

bcrypt is a password hashing function designed for secure password storage. It is widely used and well-tested, but it is specialized for password hashing and does not offer the broader range of cryptographic functionalities that libsodium provides.

README

libsodium.js

Overview

The sodium crypto library compiled to WebAssembly and pure Javascript using Emscripten, with automatically generated wrappers to make it easy to use in web applications.

The complete library weights 188 Kb (minified, gzipped, includes pure js + webassembly versions) and can run in a web browser as well as server-side.

Compatibility

Supported browsers/JS engines:

• Chrome >= 16
• Edge >= 0.11
• Firefox >= 21
• Mobile Safari on iOS >= 8.0 (older versions produce incorrect results)
• NodeJS
• Opera >= 15
• Safari >= 6 (older versions produce incorrect results)

Installation

The dist directory contains pre-built scripts. Copy the files from one of its subdirectories to your application:

• browsers includes a single-file script that can be included in web pages. It contains code for commonly used functions.
• browsers-sumo is a superset of the previous script, that contains all functions, including rarely used ones and undocumented ones.
• modules includes commonly used functions, and is designed to be loaded as a module. libsodium-wrappers is the module your application should load, which will in turn automatically load libsodium as a dependency.
• modules-sumo contains sumo variants of the previous modules.

The modules are also available on npm:

• libsodium-wrappers
• libsodium-wrappers-sumo

If you prefer Bower:

bower install libsodium.js

Usage (as a module)

Load the sodium-wrappers module. The returned object contains a .ready property: a promise that must be resolve before the sodium functions can be used.

Example:

const _sodium = require('libsodium-wrappers');
(async() => {
  await _sodium.ready;
  const sodium = _sodium;

  let key = sodium.crypto_secretstream_xchacha20poly1305_keygen();

  let res = sodium.crypto_secretstream_xchacha20poly1305_init_push(key);
  let [state_out, header] = [res.state, res.header];
  let c1 = sodium.crypto_secretstream_xchacha20poly1305_push(state_out,
    sodium.from_string('message 1'), null,
    sodium.crypto_secretstream_xchacha20poly1305_TAG_MESSAGE);
  let c2 = sodium.crypto_secretstream_xchacha20poly1305_push(state_out,
    sodium.from_string('message 2'), null,
    sodium.crypto_secretstream_xchacha20poly1305_TAG_FINAL);

  let state_in = sodium.crypto_secretstream_xchacha20poly1305_init_pull(header, key);
  let r1 = sodium.crypto_secretstream_xchacha20poly1305_pull(state_in, c1);
  let [m1, tag1] = [sodium.to_string(r1.message), r1.tag];
  let r2 = sodium.crypto_secretstream_xchacha20poly1305_pull(state_in, c2);
  let [m2, tag2] = [sodium.to_string(r2.message), r2.tag];

  console.log(m1);
  console.log(m2);
})();

Usage (in a web browser, via a callback)

The sodium.js file includes both the core libsodium functions, as well as the higher-level Javascript wrappers. It can be loaded asynchronusly.

A sodium object should be defined in the global namespace, with the following property:

• onload: the function to call after the wrapper is initialized.

Example:

<script>
    window.sodium = {
        onload: function (sodium) {
            let h = sodium.crypto_generichash(64, sodium.from_string('test'));
            console.log(sodium.to_hex(h));
        }
    };
</script>
<script src="sodium.js" async></script>

Additional helpers

• from_base64(), to_base64() with an optional second parameter whose value is one of: base64_variants.ORIGINAL, base64_variants.ORIGINAL_NO_PADDING, base64_variants.URLSAFE or s.base64_variants.URLSAFE_NO_PADDING. Default is base64_variants.URLSAFE_NO_PADDING.
• from_hex(), to_hex()
• from_string(), to_string()
• pad(<buffer>, <block size>), unpad(<buffer>, <block size>)
• memcmp() (constant-time check for equality, returns true or false)
• compare() (constant-time comparison. Values must have the same size. Returns -1, 0or1`)
• memzero() (applies to Uint8Array objects)
• increment() (increments an arbitrary-long number stored as a little-endian Uint8Array - typically to increment nonces)
• add() (adds two arbitrary-long numbers stored as little-endian Uint8Array vectors)
• is_zero() (constant-time, checks Uint8Array objects for all zeros)

API

The API exposed by the wrappers is identical to the one of the C library, except that buffer lengths never need to be explicitly given.

Binary input buffers should be Uint8Array objects. However, if a string is given instead, the wrappers will automatically convert the string to an array containing a UTF-8 representation of the string.

Example:

var key = sodium.randombytes_buf(sodium.crypto_shorthash_KEYBYTES),
    hash1 = sodium.crypto_shorthash(new Uint8Array([1, 2, 3, 4]), key),
    hash2 = sodium.crypto_shorthash('test', key);

If the output is a unique binary buffer, it is returned as a Uint8Array object.

Example (secretbox):

let key = sodium.from_hex('724b092810ec86d7e35c9d067702b31ef90bc43a7b598626749914d6a3e033ed');

function encrypt_and_prepend_nonce(message) {
    let nonce = sodium.randombytes_buf(sodium.crypto_secretbox_NONCEBYTES);
    return nonce.concat(sodium.crypto_secretbox_easy(message, nonce, key));
}

function decrypt_after_extracting_nonce(nonce_and_ciphertext) {
    if (nonce_and_ciphertext.length < sodium.crypto_secretbox_NONCEBYTES + sodium.crypto_secretbox_MACBYTES) {
        throw "Short message";
    }
    let nonce = nonce_and_ciphertext.slice(0, sodium.crypto_secretbox_NONCEBYTES),
        ciphertext = nonce_and_ciphertext.slice(sodium.crypto_secretbox_NONCEBYTES);
    return sodium.crypto_secretbox_open_easy(ciphertext, nonce, key);
}

In addition, the from_hex, to_hex, from_string, and to_string functions are available to explicitly convert hexadecimal, and arbitrary string representations from/to Uint8Array objects.

Functions returning more than one output buffer are returning them as an object. For example, the sodium.crypto_box_keypair() function returns the following object:

{ keyType: 'curve25519', privateKey: (Uint8Array), publicKey: (Uint8Array) }

Standard vs Sumo version

The standard version (in the dist/browsers and dist/modules directories) contains the high-level functions, and is the recommended one for most projects.

Alternatively, the "sumo" version, available in the dist/browsers-sumo and dist/modules-sumo directories contains all the symbols from the original library. This includes undocumented, untested, deprecated, low-level and easy to misuse functions.

The crypto_pwhash_* function set is also only included in the Sumo version. The high amount of heap memory (allocated after loading) required by these functions may not be desirable when they are not being used.

The sumo version is slightly larger than the standard version, and should be used only if you really need the extra symbols it provides.

Compilation

If you want to compile the files yourself, the following dependencies need to be installed on your system:

• emscripten
• binaryen
• git
• nodejs
• make
• uglify-es (yarn global add uglify-es)

Running make will clone libsodium, build it, test it, build the wrapper, and create the modules and minified distribution files.

Authors

Built by Ahmad Ben Mrad, Frank Denis and Ryan Lester.

License

This wrapper is distributed under the ISC License.