I had this idea, and decided to make it. I'm not an expert in cryptography, so please tell me if there's a flaw in my logic. If not, feel free to try this out at
4coin.co.nr. Here's the text from the about page:
4Coin may sound like 4chan, but it isn't really an image board. It's closer to an anonymous forum. But, there's one thing that makes this forum different from other anonymous forums/image boards. This forum uses Bitcoin keys to sign and verify messages client side, so that you can trust that you're talking to the person with the corresponding Bitcoin address. All you have to do is enter your private key (Sipa, Hex, or Base64 format) into the text box labled "Private Key," enter a topic (if you're creating a thread,) and message, click the "Sign Message" button, and then click the "Post" button. Then, your thread or reply will be posted, and people can see whether your message is successfully verified by your public key or not. Your private key is never shared with the server! When you click "Sign Message," your private key is used to sign the message, and find your public key. Then when you click "Post," the only data that is sent to the server is your topic, (if you are creating a thread,) your message, your public key, and the signature. When people view your thread or reply, the page uses your public key and signature to verify the message. If the message is successfully verified, an image will appear at the bottom of your post saying "Verified." If not, you'll get a big fat "Nope!" Messages are parsed using Markdown syntax. If you don't have a private key and Bitcoin address, or you don't know how to get the private key from your Bitcoin address, you can get a new private key and address at:
bitaddress.org
The site uses bitcoinjs-lib to sign and verify messages on the client side. The original idea was to verify messages on the server side, so only verified messages would get through, but I had some trouble, so now messages are verified client side too.
