# Proof of Work Captcha

## What's Happening? Why Are My Fans Spinning Up?

When you click the "Verify Me" box, the Proof of Work Captcha safely runs
a small piece of JavaScript code within your Browser's sandbox. This code
solves a mathematical puzzle that is quite processor intensive.

Whenever your Browser finds a solution to this puzzle, it sends it over
to our servers where it is verified. Once your Browser has submitted enough
valid solutions, our servers will allow you to submit the form.

This essentially works like Google's *reCaptcha* (you know, the one
where you have to *“proof you're human”* by selecting all street
signs from a bunch of images). This captcha however lets your Browser
do all the work.

## Why Is It Taking So Long?

Depending on your Computer, solving these mathematical puzzles can take quite some
time. The faster your Computer is, the faster the Proof of Work Captcha will
be solved.

Smart phones or tablet's are especially slow at this. If you want it to run
faster, use a Laptop or Desktop Computer.

Updating your Browser can also help tremendously. Use a browser that has support
for WebAssembly, such as Chrome or
Firefox.

## What Exactly Is Computed Here?

The *mathematical puzzle* is the hashing algorithm for the
Monero Blockchain.
Monero is a Crypto Currency, not unlike Bitcoin. We use Monero, because its
hashing algoritm (*Cryptonight*) runs especially well on consumer CPUs.

Essentially, you're *mining* XMR - the currency for the Monero Blockchain.
With each hash you solve, you create a tiny bit of XMR, less than one one-thousands
of a dollar cent. But it all adds up.

The proceeds go to the authors of the Website and help to cover their costs.

You can embed this captcha in your own website, too and let your users mine
XMR for you. Have a look at coinhive.com for the details.