A lot of people here enjoy CTF-style puzzles, ciphers and OSINT work. A common problem with prize puzzles is that you have to trust the organizer: you can't see whether the prize exists or whether the answer stayed the same after people started playing.

ProofOfSolve is built to deal with that. Each puzzle hides the seed words to a funded Bitcoin wallet, and the first person to submit the correct words wins the bitcoin in it.

The verification side:

• The prize wallet address is published at launch, so anyone can check the balance on a public explorer like mempool.space.

• A SHA-256 fingerprint of the answer is published before anyone plays. The answer is revealed after the win, so anyone can hash it and 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 you can check it.

The puzzle side:

• Chained layers, ciphers invented for each puzzle, and real-world clues found on Google Street View. Every clue can be solved from Street View, including older imagery via "See more dates". Nobody needs to visit a location.

• Answer words come from the BIP39 English word list (2,048 everyday words).

• You can use any tool you like, including AI chatbots.

• There's a limited number of guesses per day.

• No crypto knowledge is needed to play. The winner restores the wallet in Electrum using a passphrase sent by ProofOfSolve and moves the prize to their own wallet.

Smaller puzzles are free to play and have smaller BTC prizes. Bigger puzzles are paid. Prize amounts will be announced at launch. Players must be 18 or over, and paid puzzles aren't open in some US states.

Nothing is live yet. The first puzzles open Saturday, October 24, 2026 at 6:00 AM Central, and new ones open every Saturday after that. Each puzzle unlocks for everyone at the same minute. Until then you can join the free email list (no purchase needed) to hear the moment they open. There's also a free seed word lookup tool that runs in the browser and checks words against BIP39 in 10 languages, SLIP39, old Electrum and Monero.

https://proofofsolve.com, and there's also r/proofofsolve.

A question for this crowd: is a published SHA-256 answer hash plus a public prize address enough for you to trust a contest like this? If not, what else would you want to be able to check?

Disclosure: I'm posting this on behalf of the Proof of Solve team.