The Coldcard Disaster: Everything You Need to Know | Lloyd Fournier & Nick Farrow

— A catastrophic Coldcard vulnerability in randomness generation affected approximately 1,200 wallets and nearly 2,000 Bitcoin, exposing years of stacking by users who followed best practices like self-custody.

— The bug stemmed from Coldcard's use of the non-cryptographic Yasmarang RNG layered on top of device entropy, compressing the effective entropy to just 20–40 bits instead of 256 bits required for security.

— An AI model (Grok/Claude/Kimmy-K3) discovered and exploited the vulnerability; multiple human reviewers, security audits, and safeguards all failed to catch five years of weak randomness.

— Dark Skippy is a two-signature attack where a malicious device can leak a seed phrase through transaction nonces, demonstrating that hardware wallets remain trusted third parties regardless of air-gapping or entropy controls.

— Distributed key generation and threshold signatures (Frost) used by Frostsnap eliminate single points of failure in randomness and remove the need for descriptor backups, improving recovery and inheritance.

— The community debate now centers on whether users should roll dice, use multiple devices from different manufacturers, or accept that single-sig custody may require fundamental rethinking.

— If you hold Bitcoin on a Coldcard Mark III, move funds immediately; Mark IV and V are harder but not impossible to crack. Verify recovery and prioritize geographic distribution of keys across trusted people and locations rather than keeping all entropy in one physical space.

— Adopt multi-vendor multi-signature setups (three different manufacturers, two-of-three spending) or Frost-based solutions that do not require descriptor backup management, reducing single points of failure from both device entropy bugs and human error.

— Recognize that hardware wallets are trusted third parties; no amount of dice rolling or air-gapping eliminates the risk of malicious firmware. Plan inheritance and custody for family by keeping keys or backups with trusted contacts during office hours, not all in your home.