Bitcoin Forum

WalletBit is pleased to give the Bitcoin community BitcoinCAPTCHA. This is a new method of ensuring users filling out forms are real people using Bitcoin. There is no charge for using the service and the BitcoinCAPTCHA can be fully customized.

BitcoinCAPTCHA replaces the standard CAPTCHA with a QR code where any amount of Bitcoins must be sent. It is also URI wallet compatible, providing effortless payments from someone logged into a URI wallet service. Simple instructions on how to use BitcoinCAPTCHA are included, along with source code and a template for your own custom CSS.

https://bitcoincaptcha.com/

https://bitcoincaptcha.com/includes/bitcoinCAPTCHA.png (https://bitcoincaptcha.com/help)

Cool idea but what stops a tool from reading the QR code and sending a payment? :O

That's not the point. The point is to make each attempt cost a bit of wealth which is basically meaningless to an actual user but which will add up to being very expensive for someone who wants to use a bot.

This was a long time coming and I'm very happy someone put the work into it and made it happen!

Technically there is nothing preventing someone from doing this but OCR could be used to defeat text CAPTCHA as well. With BitcoinCAPTCHA it will cost them more to bypass your CAPTCHA screen, adding a monetary deterrent.

Nice implementation!

When creating LBAAT.net, I suggested something similar - you send coins to yourself, but in the future. The card provided would have the user's public key, and send coins to an address that won't be revealed until tomorrow, next week, etc.

Only the monetary deterrent is the issue here. (Arguably whether it is good.)
OCR is much harder to do than scan barcodes, which are basically engineered to be scanned very easily.

I'm curious how these problems are overcome (if they are actually problems):

Since a fee is charged to fill out the form, the site would have to decide on a fee that would discourage spam bots, but not discourage legitimate users.

If 1 confirmation is required, then the user has to wait an average of 10 minutes before continuing. If no confirmation is required, then a bot can just double spend. I guess there are cases where a 10 minute delay is not a problem.

This requires the availability of another device that can scan the QR code, plus access to a wallet (which could potentially be on a third device).

We feel the current default fee of 0.0005 BTC strikes a good balance but it can be changed in the script.


No confirmations are required since it would be impractical for a CAPTCHA.


WalletBit Mobile  (https://walletbit.com/mobile)has all this functionality built in (including QR recognition) as do other services. There is also built in URI compatibility - If your wallet service is URI compatible there is no need for an external device. WalletBit (https://walletbit.com) is URI compatible.   

Which scenarios does this fix?  I'm trying to think of a scenario in that a service would want to charge their users (even a small fee) just to stop some bots from abusing the service.  Sounds like an unnecessary fee on users just for deterring bots... plus if its actually worth it a bot could easily be programmed to complete the CAPTCHA, which, in my opinion, defeats the purpose of a CAPTCHA.

Not trying to talk down about this service, its a well done implementation, I'm just trying to see where it could be used.  Has anyone put this to use yet?

Text-based CAPTCHAs are fine, and if made right won't be broken by OCR.  Also for services that allow you to pay $x for y amount of text-based CAPTCHA answers, couldn't people just now do it easier by pumping that money into Bitcoin and complete the CAPTCHA by paying the small fee? Basically what I'm saying is this is if a person wants to get around a CAPTCHA... they will... adding an inconvenience such as scanning a QR code is something most users will not want to do. Especially if its taking their precious Bitcoins!

I just got tired of not being able to read the captcha's that I decided to make a bitcoin one. I read here and there that people might also be interested in this, so I though hey what the hell, lets make a good Bitcoin CAPTCHA implementation.

It is primarily a way to promote that you like Bitcoin and the idea was to use it on something like the Bitcoin Wiki, because why should people edit the Wiki, if they don't even have a bitcoin wallet?

But it is just one of many side project that we develop, when there is nothing else to do. You all know by now, that I hate to sit still.

If you need another purpose for bitcoinCAPTCHA it could be utilized for news articles, so if you wanted to read an article you would first need to complete the challenge, in this case sending 0.0005 to bitcoinCAPTCHA, we all know paid news on the internet is coming one way or another.

We fully intend on sending bitcoins received though bitcoinCAPTCHA to the webmasters bitcoin address along the road, or sending it back to the user, maybe even create a bitcoin faucet. But for now lets see if there are any interest at all for further development.

I'll love to see what people can come up with using this in their projects as the most part of bitcoinCAPTCHA is customizable with CSS. You are more than welcome to post your project in which you are using bitcoinCAPTCHA in this thread.

Walletbit might want to start using it on their own site spending a good portion of my time fighting the captcha signing up ....about to give up.... ???

That's the plan. Yes I'm giving up on reCAPTCHA as well.

This is a really cool project. I could see it being very useful for bitcoin sites, as long as it confirms quickly. Sux for people who don't have a smart phone though.

If you click the QR code on https://bitcoincaptcha.com or any other place where it has been implemented and have a Bitcoin Wallet installed, it will automatically open up with the predefined amount to complete the challenge. No need for a smart phone. Try it out and see if it works for you.

BitcoinCAPTCHA is now implemented on WalletBit. If you refresh the signup page you should be able to see it now.

there are still no bitcoin wallets in existence that cater to 'subscription-based' services, that do an automatic push of funds to merchants  periodically. top-up or auto-expire the subscription, etc. 3-day trial, followed by 30-day rollover... so much potential for customization.

nice captcha thingy though, by the way.

Yes there is, worlds first bitcoin subscription solution even. I have just not been very good at promoting it.

https://walletbit.com/docs/subscriptions

well, wow, that one did indeed fly under the radar.

Indeed, you will also find a WHMCS subscription plugin at https://walletbit.com/shop

Use the paid content idea and develop a WordPress plugin to hide a part of a post before the captcha is passed and you may have a winner.
I would start using it on some websites that get some nice traffic and instruct users to use the faucet if they don't have bitcoins.

Very nice idea for use of Bitcoin's micropayment capabilities. Let's hope this gets some press.

Yes I agree the pay to view idea is great. Using for CAPTCHA might have been a limiting way to market this :).

As requested, https://bitcoincaptcha.com/apis/wordpress

Great stuff Kris. Thanks a lot.
Gonna implement it at the first site tomorrow.
Not expecting to make money with it but for sure every one of those who see this captcha will know what bitcoin is.

How did it work out?

Christmas and New Year got in the way. ;)
The plugin is already installed, but only working on 1 post and it won't be easy to make it work on older posts without editing each one of them, so I'll probably use it only on new posts, which I'll start making again in the next couple days.