The challenge has not yet been released, it is from an early adopter and if it's worth it, not only for the prize of around 300 BTC, but for how difficult they are. The creator has already made a challenge before. https://www.reddit.com/r/Bitcoin/comments/9kq7it/introducing_the_310_btc_bitcoin_challenge/ (it was the previous one) I tried to look for people in reddit but everyone criticized me saying it was a scam or something similar. Thanks.