Argon2 in browser

Argon2 is a password-hashing function, the winner of Password Hashing Competition. Here Argon2 library is compiled for browser runtime.

Live demo

More about Argon2

Usage

The numbers

	Time, ms (lower is better)
Chrome WASM	360
Firefox WASM	340
Safari WASM	310
Native -O3 SSE	90
Native -O3	140
Native -O1	300
Native -O0	750

Test Environment

Environment used to get the numbers above:

Algorithm parameters (-d -t 100 -m 10 -p 1):

• iterations: 100
• memory: 1MiB (1024 KiB)
• hash length: 32
• parallelism: 1
• argon2d

Environment:

• MacBook pro, Intel Core i5, 2.5GHz (x64), macOS 10.14.6 (18G95)
• Chrome 76.0.3809.100 (Official Build)
• Firefox 69.0.1
• Savari v13.0 (14608.1.49)
• native argon2 compiled from https://github.com/P-H-C/phc-winner-argon2 @4844d2f

Code size

File	Code size, kB
argon2.js	16
argon2.wasm	31

Is Argon2 modified?

The only change is disabling threading support.

Difficulties

Argon2 is using uint64, which is not supported by JavaScript. This function is called ~30M times per one iteration:

uint64_t fBlaMka(uint64_t x, uint64_t y) {
    const uint64_t m = UINT64_C(0xFFFFFFFF);
    const uint64_t xy = (x & m) * (y & m);
    return x + y + 2 * xy;
}

And this one:

uint64_t rotr64(const uint64_t w, const unsigned c) {
    return (w >> c) | (w << (64 - c));
}

In C++, we can make use of SSE for 64-bit arithmetics. In JavaScript, when no 64-bit unsigned long type is available, different engines have different time penalties of this operation.

WASM can support 64-bit integers but it requires compilation with LLVM, and not as asm.js => wasm. But this build is producing bad wasm for now. A simple experiment can be found in perf-test.c: compiling it with i64 support in LLVM gives us 4x boost.

JS Library

Until WASM is mature, js library is using only asm.js. Here's how to try it.

Install with npm:

npm install argon2-browser

Add script to your HTML:

<script src="node_modules/argon2-browser/lib/argon2.js"></script>

Calculate the hash:

argon2.hash({ pass: 'password', salt: 'somesalt' })
    .then(h => console.log(h.hash, h.hashHex, h.encoded))
    .catch(e => console.error(e.message, e.code))

Verify the encoded hash (if you need it):

argon2.verify({ pass: 'password', encoded: 'enc-hash' })
    .then(() => console.log('OK'))
    .catch(e => console.error(e.message, e.code))

Bring your own bundler and promise polyfill.
Other parameters:

argon2.hash({
    // required
    pass: 'password',
    salt: 'salt',
    // optional
    time: 1, // the number of iterations
    mem: 1024, // used memory, in KiB
    hashLen: 24, // desired hash length
    parallelism: 1, // desired parallelism (will be computed in parallel only for PNaCl)
    secret: new Uint8Array([...]), // optional secret data
    ad: new Uint8Array([...]), // optional associated data
    type: argon2.ArgonType.Argon2d, // or argon2.ArgonType.Argon2i
    distPath: '' // asm.js script location, without trailing slash
})
// result
.then(res => {
    res.hash // hash as Uint8Array
    res.hashHex // hash as hex-string
    res.encoded // encoded hash, as required by argon2
})
// or error
.catch(err => {
    err.message // error message as string, if available
    err.code // numeric error code
})

Usage

You can use this module in several ways:

1. write the WASM loader manually, for example, if you need more control over memory (example);
2. bundle it with WebPack or another bundler (example);
3. in vanilla js: example;
4. in node.js: example (see a note below).

Node.js support

Of course you can use generated asm.js code in node.js but it's not sensible: you will get much better speed by compiling native node.js addon, which is not that hard. Wait, it's already done, just install this package.

Is it used anywhere?

It is! KeeWeb (web-based password manager) is using both asm.js and WebAssembly Argon2 implementations. Check out the source code, if you're interested.

Building

You can build everything with

./build.sh

Prerequesties:

• emscripten with WebAssembly support (howto)
• CMake

License

MIT