INVESTIGATIVE DOSSIER · RESEARCHED 03 OCT 2026
BITCOIN PUZZLE #47 · 47-BIT · SOLVED

Bitcoin Puzzle #47

Solved and swept on 01 Sep 2015. The private key for this 47-bit puzzle was found inside [2^46, 2^47) and the balance was moved out.

Why puzzle #47 still matters

A solved puzzle is a benchmark. Running a cracker against it should recover the real private key, which is how you tell genuine code from a toy. Puzzle #47 needs about 2^45 key tests on average.

Re-solve #47 in your browser All 256 puzzle addresses