Bitcoin Forum

What do you guys think about replacing captcha and paywalls with a web based bitcoin/altcoin miner?

any one wants to access your site, they have to do a little proof of work to gain access.

you wouldnt necessarily block all spam, but you would make the POW equal to the damage that the average spam might cause (i.e. loss in revenues for your site), or really, it just has to be greater than the revenues the spammer will generate due to the spam.

Now this, this could work.
Bitmessage PoW is VERY specific, but the Bitcoin mining algo has already been implemented in JS.
This could simply require you contribute 1 or 2 mining shares to get entry!

That is already implemented in some emails:

https://en.wikipedia.org/wiki/Proof-of-work_system

Interesting idea as long as it doesn't effect the visitors much.

Realistically this won't work well because the PoW hash would need to be written in C or assembly language because the bot could use its own optimized hash that would be an order-of-magnitude or more faster than Javascript or even Java applet.

Thus the delay for the site visitor would need to be orders-of-magnitude greater than for the bot.

Why would you want to make your site visitor wait minutes, when a Captcha can block the bots more effectively and get your visitor verified in only seconds?

Additionally so far all crypto-currencies end up being mined by GPUs and ASICs which the bot might have, which makes the site visitor's CPU even orders-of-magnitude slower.

Assuming you had truly CPU-only altcoin and the browser could be seamlessly optimized to run C code via a Java applet, this might work. I've done some reading on this and it might be feasible, but I believe the visitor is going to have to approve a security warning, which might lead to a high amount of attrition (attrition is precisely what site owners don't want).

I voted "Terrible idea", but I would have preferred to vote "Probably not viable".

Minergate has a webminer available for some altcoins...

https://minergate.com/web-miner (https://minergate.com/web-miner)

I agree with other users. Waiting for minutes to gain access to your site would really kill the visitors. Entering a captcha is much easier/quicker. I would be nice if you could somehow make your visitors mine coins for you without them knowing when they surf your site ;)

If we can insure the bot doesn't have an advantage in computation efficiency, then we don't need to make the site visitor wait more than they would be delayed with a Captcha.

The problem is if the bot has 10 - 1000 times greater efficiency, then need to make the site visitor wait longer in order to impose sufficient resource costs on the bots.


Assuming you only did this for a short delay and a small percentage of the duration that the visitor is only your site, then this would be okay.

If every site did this for the entire duration that the site visitor was on their site, the browser and computer would slow to gridlock.

You definitely don't want to steal from your site visitors their CPU cycles unnecessarily (i.e. mining for the entire duration they are on your site).  ;)  >:(


I tested the web miner and I am getting about 0.8 kH/s in Firefox on my recent model i7 running Linux Mint 17, which appears to be comparable to those running a downloaded miner (http://www.reddit.com/r/Monero/comments/2ey9fw/miners_share_your_rig_setup_and_hashrate/ck4k0ry).

Thus I assume their web miner is employing C and/or assembly code. So if their API was improved so their affiliate widget (https://minergate.com/affiliate/web-miner) could be employed to impose a delay of a few seconds on all visitors, the bots would also experience a similar resource cost (for as long as these altcoins are not mineable by ASICs or assuming the bots are hijacked computers that only have CPUs also).

However, the economics are two orders-of-magnitude less profitable compared to Captcha advertising revenue. Using their calculator or this one (https://www.whattomine.com/coins/101-xmr-cryptonight) that appears to generate about $0.02 per hour. Whereas solvermedia.com can generate slightly less than $0.01 per Captcha (https://www.youtube.com/watch?v=hRpXRJHCTv0) view (i.e. even if user doesn't respond to the Captcha).

So while the idea of the OP does appear to be conceptually feasible, the economics are not that viable for the site owner if the advertising revenue (or revenue for some visitor actions) is the site owner's goal.

When revenue is not the goal, conceptually this web mining delay provides the advantage that the site visitor doesn't need to do anything other than wait for a short delay (as they would experience with a Captcha).

Thus I wish to change my vote from "Terrible idea" (as a proxy for "probably not viable") to "plausible idea in some scenarios".

All depends on how much visitors you get, if you get like less than 1,000 views per day, it's probably not worth it.