npm package: @haggholm/argon2-browser
Description: Argon2 library compiled for browser runtime
Author: Antelle
Latest version: 1.5.2

# 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](https://antelle.github.io/argon2-browser)

[More about Argon2](https://github.com/P-H-C/phc-winner-argon2)

## The numbers

### :warning: they are quite old, WebAssembly is better now

To cut it short, here are the numbers.

Code run time:

![hot run](img/hot-run.png)

Init time + first run time:

![load & first run](img/load-first.png)

## 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](img/code-size.png)

|             | 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](https://github.com/antelle/argon2-browser/commit/4b8950395c8c03a888ba6f417a4001458cdd3231).

## Difficulties

Argon2 is using uint64, which is not supported by JavaScript.
This function is called ~30M times per one iteration:
```cpp
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:
```cpp
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](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:
```bash
npm install argon2-browser
```

Add script to your HTML:
```html
<script src="node_modules/argon2-browser/lib/argon2.js"></script>
```

Calculate the hash:
```javascript
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):
```javascript
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:
```javascript
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](https://github.com/ranisalt/node-argon2).

## Is it used anywhere?

It is! [KeeWeb](https://github.com/keeweb/keeweb) (web-based password manager) is using both asm.js and WebAssembly Argon2 implementations.
[Check out the source code](https://github.com/keeweb/keeweb/blob/develop/app/scripts/util/kdbxweb-init.js#L13), if you're interested.

## Building

You can build everything with
```bash
./build.sh
```

Prerequesties:
- emscripten with WebAssembly support ([howto](http://webassembly.org/getting-started/developers-guide/))
- PNaCl sdk
- CMake

## License

[MIT](https://opensource.org/licenses/MIT)