200000 BTC

Just before New Year, we sold our 200 000th bitcoin! We are very proud to have come this far and would like to thank our customers for making this happen. To celebrate this milestone, we will be giving away a total of one bitcoin!

We have created five interesting, bitcoin-related puzzles. The solution to each puzzle is a key required to start (and sometimes solve) the next. Additionally, the key will enable you to spend one of the five outputs to the prize transactions we created. The prize money for each puzzle increases with difficulty.

Puzzle Solution Reward
#1 BTC 0.1
#2 BTC 0.2
#3 BTC 0.2
#4 BTC 0.2
#5 BTC 0.3
Total BTC 1.0

BTTake a look at the prize transaction

You can claim your prize by submitting your solution, and the bitcoin address you want the bitcoins to be sent to, in the form below each puzzle. Only the first person to solve the puzzle will be able to claim the prize. However, when you spend the reward, the keyword is published on the Bitcoin blockchain*; allowing everyone to unlock the next puzzle!

Once a puzzle has been solved and its reward has been spent, we will publish the solution here.

All puzzles have been solved, the 1 BTC prize has been given away. See you next year? :)

First puzzle

Second puzzle

Third puzzle

Fourth puzzle

Fifth puzzle

  • The outputs are p2sh outputs, in the form of "<pubkey B> OP_CHECKSIGVERIFY OP_SHA256 <Hash of answer> OP_EQUAL". So upon redeeming the bitcoins, the answer is revealed to the public.