Streamable SHA1

See the demo on my web site!

I created this SHA1 class to solve a problem: many existing JavaScript SHA1 implementations choke and slow down when you try to hash large amounts of data. This is because you typically have to pass all your data as one large string into one function call. This is fine for a few kilobytes of data, but if you're hashing megabytes or more of data, it takes a lot of CPU and memory to pass huge strings around.

This SHA1 class gives you the option to stream data into your hash object over multiple calls. The class buffers and processes blocks of 64 bytes, discarding data that is no longer needed. This can speed things up significantly, especially for applications that hash data generated in a loop.

This app is distributed under the MIT License and is free software.

Dependencies

• MooTools 1.4+

Usage

By default, this class behaves like any other SHA1 class:

    var hash = new sha1().hash('data data data ');
    // 65bd90d5e213e8d03e87b5be5eeda3bc81faa772

Use the streaming mode option to hash data over multiple iterations:

    var _sha1 = new sha1();
    for (var i = 0; i < 3; i++)
        _sha1.hash('data ', {stream: true});

    var hash = _sha1.finalize();
    // 65bd90d5e213e8d03e87b5be5eeda3bc81faa772

Once you're done streaming data in, you call sha1.finalize() to hash any remaining data in the buffer and return the result.

Contributing

Please let me know if you have any suggestions for improvements. If you're code savvy, fork the project and make the change yourself! I will do my best to help if something doesn't work or isn't clear. You can find me on Twitter @rubbingalcohol