🔒 Coldcard bug: weak seeds generated since 2021, Coinkite urges users to move funds immediately Less than 24 hours after a 594 BTC theft, Coinkite published a security advisory confirming a flaw in seed generation across multiple Coldcard models. Seeds generated on Mk3 running firmware 4.0.1 (March 2021) or later have an estimated effective search space of only around 40 bits, making key recomputation a feasible industrial-scale operation. Mk4, Mk5 and Q models are also affected, producing seeds with approximately 72 bits of entropy instead of the expected 128, prior to corrective firmware releases (5.6.0 for Mk4/Mk5, 1.5.0Q for Q). Coinkite warns all affected users that "funds may be at risk" and advises moving them immediately. Tapsigner, Opendime and Satscard are not affected, as they run on different codebases. The advisory does not explicitly link the vulnerability to the 30 July theft, though the timeline is notable: Coinkite CEO NVK stated hours before the advisory that there was "no evidence of a flaw" in the device's random number generator. According to Coinkite's technical review, the bug was introduced during a 2021 migration to libsecp256k1, with the hardware entropy source effectively cut out in the process. As the company acknowledges: "The cryptographic choice was sound. The integration was not." https://t.co/5ap9wxt53y