A BIP39 brute-force specialist was able to narrow the search space using the 18 known

A 2025 case documented by a Bitcoin custody specialist involved a holder who had stored their 24-word seed phrase on a steel plate but had been using an electrolytic etching process that left the characters shallow and subject to corrosion. After several years in storage near a coastal area with salt air exposure, 6 of the 24 positions had corroded to illegibility. A BIP39 brute-force specialist was able to narrow the search space using the 18 known words as anchors and test all valid combinations for the 6 unknown positions. After approximately four days of computation, the correct seed phrase was identified and the wallet recovered.