Still unsolved. The private key for this puzzle is an integer between 2^85 and 2^86 − 1, and whoever finds it can sweep 8.60000000 BTC from 1K3x5L6G57Y494fDqBfrojD28UJv4s5JcK.
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 2^84 tests, about 1.93e+25. A single high-end GPU running BitCrack or keyhunt manages roughly a billion tests per second.
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