@pcd/libsodium-sumo
v0.7.15-1
Published
The Sodium cryptographic library compiled to pure JavaScript (raw library, no wrappers, sumo variant)
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Readme
Zupass libsodium fork
This repository is a fork of libsodium, with a custom build configuration to produce a smaller distributable, tuned for the needs of the Zupass project.
See the commit history for changes to the standard libsodium.
Below is the regular 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 weighs 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
- Bun
- Opera >= 15
- Safari >= 6 (older versions produce incorrect results)
This is comparable to the WebCrypto API, which is compatible with a similar number of browsers.
Signatures and other Edwards25519-based operations are compatible with WasmCrypto.
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 loadlibsodium
as a dependency. - modules-sumo contains sumo variants of the previous modules.
The modules are also available on npm:
Usage (as a module)
Load the libsodium-wrappers
module. The returned object contains a .ready
property: a promise that must be resolve before the sodium functions
can be used.
Example:
import _sodium from 'libsodium-wrappers';
await (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
orbase64_variants.URLSAFE_NO_PADDING
. Default isbase64_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, returnstrue
orfalse
)compare()
(constant-time comparison. Values must have the same size. Returns-1
,0
or1
)memzero()
(applies toUint8Array
objects)increment()
(increments an arbitrary-long number stored as a little-endianUint8Array
- typically to increment nonces)add()
(adds two arbitrary-long numbers stored as little-endianUint8Array
vectors)is_zero()
(constant-time, checksUint8Array
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 only included in the sumo version.
The sumo version is slightly larger than the standard version, reserves more memory, 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
- bun
- make
Running make
will install the dev dependencies, clone libsodium,
build it, test it, build the wrapper, and create the modules and
minified distribution files.
Related projects
- react-native-libsodium: React Native bindings to Libsodium matching the libsodium-wrappers package API
Authors
Built by Ahmad Ben Mrad, Frank Denis and Ryan Lester.
License
This wrapper is distributed under the ISC License.