Can I add catchpa's to cryptocurrency?

[dnhkng]

Hi guys,

I was wondering if it would be possible to add a human element to the inflationary phase of cryptocurrency generation. Right now, new currencies can be hit by speculative mining and dumping of coins; the price of dogecoin over the last few weeks reflects this. Groups with ASICS can mine the hell out of a new currency while the difficulty is low, and then dump the currency as it starts to rise. Alternative algorithms lock out those who have invested in mining hardware, which is also unfair.

I was wondering, would it be possible to add something to the block header to prevent this? My idea is to add a catchpas to images that are regularly posted to multiple image hosting sites over the internet. Miners could choose to solve the catchpa, and add the its hashed value to the header for mining. If just an acceptable hash is found, coins would be mined, but if the hash of the catchpa is also correct, a bonus multiplier would be awarded. This means that small miners would overcome a lot of the power of professional miners.

I have't thought of a distributed way to generate catchpa-marked images that can't be easily exploited. Maybe a benevolent dictator system would be OK, or open source code could run on a public server, paid for by a transaction fee? I see this more as a issue for a new cryptocurrency, where it would be nice to let new users join without being crowded out by the big-rigs, but also let those who have invested in hardware compete fairly.

I would love to hear some constructive criticism!

[W-M]

I think this is problematic, if not impossible, to implement.




There are many services on the internet which have people (and also computer algorithms, for the easier ones) solve captcha's for you for a very small amount of money. And even if a block is solved approximately every 30 seconds, a human can solve multiple captchas during that timespan.

And then of course you have the issue of where the captcha's come from: If one server designs them, then the currency is no longer decrentralized. If every node can come up with the captcha on its own, what prevents tinkerers to exploit the captcha-generation code to solve them automatically?

A captcha is a known message that is relayed to another entity in a way that only humans should be able to interpret it. Thus, the service creating the captcha already knows the answer, and could skip the process entirely.


In my own opinion, the best idea to prevent pump 'n dump schemes is to make the coin distribution curve not too steep (e.g. not give away most coins in the first few blocks). Besides that, I think that creating a coin where using the mining hardware created for Bitcoin (or even the rigs made for Litecoin) is impossible is not unfair, and instead creates a much more equal distribution.

After all, ASICs and FPGAs existed before Bitcoin, but not ones that would be able to mine Bitcoins. Is this unfair?


My two cents. There are lots of other unexplored interesting ideas that one can come up with. Most of them wont work, but some might. I'd say: Keep on thinking.

~W-M

[stompix]

It would be easier to make a limit on the hashpower that anyone can contribute to the network rather than implementing a captcha.
This could be in theory at least be achieved with a new algorithm. I saw this idea a few times but not a step towards practice.

But again , an easier way is to get the right numbers with the coin reward per block to encourage adoption but not heavy mining.
Not 50% of them in the first blocks but not 0.001%.

[lololol3]

This is something Ive been thinking about for long...
How to make more egalitarian coin?
I am thinking about creating Egalitairan Coin or something like this. A coin that will be much more equal through the society, and not only for GPU rig owners or asic miners. There must be some kind of human element in it...
If you want to talk about this hit me up at mailingbot[at]gmail.com or lets create some kind of board or irc for this. I have some ideas but none of them is for now computer-proof and captha isnt perfect i think, but its some solution.

We need to think about something that is easy to solve for anyone but computer cant do this.

Maybe some kind of simple riddles created by community? They get voted, and after certain time they dissapear?
You need to solve for example every 1 hour. If you are at the computer then its okay. But if you run 100 CPUS on a digitalcloud then its not worth it to sit and solve it 24h a day

[dnhkng]

Thanks for the analysis. I have a few replies to your points 

I think this is problematic, if not impossible, to implement.

There are many services on the internet which have people (and also computer algorithms, for the easier ones) solve captcha's for you for a very small amount of money. And even if a block is solved approximately every 30 seconds, a human can solve multiple captchas during that timespan.

And then of course you have the issue of where the captcha's come from: If one server designs them, then the currency is no longer decrentralized. If every node can come up with the captcha on its own, what prevents tinkerers to exploit the captcha-generation code to solve them automatically?

A captcha is a known message that is relayed to another entity in a way that only humans should be able to interpret it. Thus, the service creating the captcha already knows the answer, and could skip the process entirely.

~W-M

I just found out about verifiabling computing http://research.microsoft.com/apps/pubs/default.aspx?id=180286, from this thread: https://bitcointalk.org/index.php?topic=277389.0 which might solve at least the technical problems. Each client, when solving a block, could add a catchpa to an image using a fixed algorithm with random seed data, and use verifiable computing to prove that it followed the rules.  As new and better catchpa generators are invented, they could be implemented in upgrades.

There is only one catpcha per block, and the cost of paying someone, even a cent per captchpa, would be higher than electricity costs, and as there is only one catchpa to solve, every say 5 minutes, it would be very inefficent to pay someone for just solving 12 catchpas per hour.

To stompix: I think it would easy to generate lots of workers to get around any fixed limit on hashing power. As they are all anonymous, detecting multiple workers from one individual wouldmbe hard.

Lololo3:  yeah, this is exactly the direction I want to go in. The whole system is to extend the dogecoin fun model for cryptocurency. But dogecoin was heavily mined by the old rigs from litecoin/bitcoin miners, which kind of broke it.

[Nullu]

It's an interesting idea to have a coin this is mined by human input, but it'd have to be clever to avoid being mined by auto responders.