Coldcard Issues Security Firmware After Hack, Tells Users to Replace Seed Phrases

Coinkite, the maker of the Coldcard hardware wallet, has released new firmware to strengthen security in seed-phrase generation after a major hack.

Cointelegraph reported on Aug. 21 that Coinkite published firmware version 5.6.1 for the Coldcard Mk4 and Mk5, and version 1.5.1Q for the Coldcard Q.

The new firmware uses not only random values generated by the device itself when creating a wallet's seed phrase, but also random information entered by the user, Coinkite said. The change is intended to make it harder for attackers to predict a private key even if part of the device's internal random-number generation process malfunctions.

Coinkite also recommended that users update their firmware immediately and replace existing seed phrases. Updating the firmware does not restore the safety of seed phrases generated under the older vulnerable method, the company said. Users should create a new seed phrase after updating and move existing assets to a new wallet.

The update is part of the company's response to a recent large-scale Bitcoin theft involving Coldcard wallets. The total amount stolen from Coldcard wallets has reached 1,778 Bitcoin, according to the report.