INVESTIGATIVE DOSSIER · RESEARCHED 03 OCT 2026
BITCOIN PUZZLE #39 · 39-BIT · SOLVED

Bitcoin Puzzle #39

Solved and swept on 21 Jan 2015. The private key for this 39-bit puzzle was found inside [2^38, 2^39) and the balance was moved out.

Why puzzle #39 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 #39 needs about 2^37 key tests on average.

Re-solve #39 in your browser All 256 puzzle addresses