Many of us enjoy the crypto and OSINT parts of CTFs. Outside of a live event, though, there aren't many puzzle hunts where the prize is real and you can check for yourself that the organizer played fair.
ProofOfSolve is trying to fill that gap. Each puzzle hides the seed words to a funded Bitcoin wallet, and the fastest correct solver wins the bitcoin in it. The puzzles chain layers together, use ciphers invented for each puzzle, and include real-world clues found on Google Street View. Every clue can be solved from Street View, including older imagery via "See more dates", so nobody needs to visit a location.
I think the verification side is what this sub will care about most:
- The prize wallet address is published at launch, so you can check it on a public explorer such as mempool.space.
- A SHA-256 fingerprint of the answer is published before anyone plays. The answer is revealed after the win, so anyone can confirm it never changed.
- Entries are timestamped to the millisecond, and the first correct entry wins.
- Past puzzles are listed with prize address, answer fingerprint, solve time and payout, each linked so anyone can check it.
Some practical details. Answer words come from the BIP39 English word list (2,048 everyday words). You can use any tool you like, AI chatbots included. You get a limited number of guesses per day. The winner restores the wallet in Electrum using a passphrase sent by ProofOfSolve, then moves the prize to their own wallet. You don't need any crypto knowledge to play.
Smaller puzzles are free to play and have smaller BTC prizes. Bigger puzzles are paid. Prize amounts are announced at launch. Players must be 18 or over, and paid puzzles are not open in some US states.
Nothing is live yet. The first puzzles open Saturday, October 24, 2026 at 6:00 AM Central, and each one unlocks for everyone at the same minute. New puzzles open every Saturday after that. Joining the email list is free, needs no purchase, and tells you the moment puzzles open. The site also has a free seed word lookup that runs in your browser and checks words against BIP39 in 10 languages, SLIP39, old Electrum and Monero.
https://proofofsolve.com
This sub has a no-spoilers rule, so once puzzles are live, please take talk about specific puzzles to r/proofofsolve and keep it out of here.
A question for people who run or play CTFs: is a pre-published hash commitment plus a public prize address enough for you to trust a contest like this? Or is there something else you'd want to see before putting time into it?
Disclosure: I'm posting this on behalf of the Proof of Solve team.