INVESTIGATIVE DOSSIER · RESEARCHED 03 OCT 2026
BITCOIN PUZZLE #128 · 128-BIT · OPEN

Bitcoin Puzzle #128

Still unsolved. The private key for this puzzle is an integer between 2^127 and 2^128 − 1, and whoever finds it can sweep 12.80000000 BTC from 1MZ2L1gFrCtkkn6DnTT2e4PFUTHw9gNwaj.

How to attempt Bitcoin puzzle #128

Only the address is known, so a solver has to walk the interval: multiply the secp256k1 generator by each candidate key, hash the compressed public key with SHA-256 and RIPEMD-160, and compare with the address’s hash160. On average that is 2^126 tests, about 8.51e+37. A single high-end GPU running BitCrack or keyhunt manages roughly a billion tests per second.

Try cracking #128 in your browser How solvers really attack it