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

The numbers

⚠️ they are quite old, WebAssembly is better now

To cut it short, here are the numbers.

Code run time:

Init time + first run time:

Numbers in table (ms, lower is better)

	Load	First Use	Second Use
Native -O3 SSE	0	90	90
Native -O3	0	140	140
Native -O1	0	300	300
Native -O0	0	750	750
Chrome asm.js	100	7500	6800
Chrome WASM	350	1700	1650
Chrome PNaCl	1500	200	200
Chrome Interpret s-expr	1000	1650000	1650000
Chrome Interpret binary	800	1800000	1800000
Firefox asm.js	360	1850	1700
Firefox WASM	400	1750	1650
Safari asm.js	100	7500	6900
IE11 asm.js	100	52000	47000
Edge asm.js	65	19500	18000
Edge +asm asm.js	100	2900	2850

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)
• Chrome 55.0.2843.0 (Official Build) canary (64-bit), V8 5.5.1
• Firefox Nightly 51.0a1 (2016-08-29)
• IE11 and Edge on Windows 10 (x64, Bootcamp)
• native argon2 compiled from https://github.com/P-H-C/phc-winner-argon2 @4844d2f

Code size

It's hard to measure WebAssembly code size because the project is not finished yet and the size of wrapper is rather large. So, we measure only binary file size (.wasm).

	Code size, kB	Comment
asm.js	109	complete
WebAssembly	43	only .wasm
PNaCl	112	.pexe

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)
    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
})

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)
• PNaCl sdk
• CMake

License

MIT