Sort:  

isn't this undecryptable?

You can decrypt answer only if you know the key. In this case solution is the key.

ahh, so this is how it works. Can you please explain to me how to use it?(if I want to run a contest)
I'm not joining tho.

In the post you can find instruction how to encrypt the answer. There is a link to webpage where you have to put your nickname in text field and put answer from puzzle as a encryption key. Then just click "encrypt" button and copy the result and paste in comment. That's all :)

ok thanks man :D