Bitcoin Forum

Hi there,

during the last year I put a lot of effort into creating a bitcoin riddle website which is now up since a few weeks (bitcoinriddles.com).
This is a non-commercial project that I did for fun and hopefully it introduces some new people to bitcoin.

There are however a few things I'm struggling with, maybe some of you guys have some ideas on how to solve this:

1) The site should also be usable by people not familiar with bitcoin (would be nice to introduce some new people to bitcoin). When they solve a riddle they can choose between:
a) direct transfer to BTC address (for experienced users)
b) email from coinbase, in that case they need to create a coinbase account when receiving the email in order to get the bitcoin
-> I would very much like to get rid of the coinbase API. But so far I really did not find any other way of easily transfering some bitcoin to people that have no clue about bitcoin. (e.g. paper wallet via email would be very risky as I am sure people would not be able to correctly swipe the paper wallet. Also I cannot assume that people already have a bitcoin wallet at the time when they solved a riddle)

2) I am currently only rewarding the user that solves the riddle first (right now usually 10000 bits per riddle). I therefore have to make the riddles quite hard so they don't get solved too quickly. This is probably putting off some users. I would very much like to reward also other users even when they have not solved it first, e.g. first 10 solvers get some reward as well.
-> The problem there is however, how can I prevent a user from just creating 10 accounts and getting all the rewards? (This would be a kind of sybil problem ;) )

Thank you for any suggestions!

You could prevent users from registering from the same IP multiple times. You could also check if they are coming from an IP associated with TOR or a known proxy and prevent those users from registering.

It says invalid username, can only contain letters and numbers. How is "TBZ1" not letters and number?