The Bitcoin Puzzle Challenge, a decade-old onchain bounty system, still holds roughly 916.52 BTC — worth about $58.87 million at current prices. This week, community solvers cleared Puzzle 70 and set their sights on the next target: a 71-bit keyspace. But pool telemetry suggests brute-forcing that level could take centuries.
The decade-old bounty
The challenge first appeared on the blockchain years ago, offering rewards for cracking progressively harder private keys. Each puzzle is a transaction with a small amount of BTC that can only be moved if someone finds the correct key. Over the years, solvers have chipped away at the list, but the biggest prizes remain locked.
Puzzle 70 cleared
Solving Puzzle 70 was no small feat. It required scanning a 70-bit range — a space of about 1.18 quintillion possibilities. The solver or group that cracked it earned the BTC locked in that transaction. Now the community is turning its attention to Puzzle 71, which bumps the difficulty to a 71-bit keyspace.
The 71-bit wall
That next jump is brutal. Pool telemetry data indicates that brute-forcing the 71-bit target with current hardware and methods would likely take centuries. That doesn't mean it's impossible — just that the math isn't on the solvers' side. The challenge might sit untouched for a long time, unless someone finds a smarter way to attack it.
For now, the bounty sits there, waiting. The next move belongs to the solvers — or to whoever can figure out a shortcut the original creator didn't anticipate.
