Hi all.

You’ve probably seen the Coldcard news by now. If you haven’t, or you're not sure whether you’re affected, please start here rather than with anything I’ve written:

🚨 If you own a Coldcard, assume you’re affected until you've checked.

Seeds generated on a Mk2 or Mk3 running firmware 4.0.1 up to and including 4.1.9 are effectively guessable. Seeds from a Mk4, Mk5, or Q are far weaker than advertised. Updating the firmware does not make you safe; you’ll need to move your funds. Read the official statement from Coinkite.

Once you're safe, I’ve written up where I’ve landed on all this.

There’s a short technical summary of what actually went wrong, a look at whether a flaw like this could ever have been responsibly disclosed, my thoughts on the role of AI, and an attempt to work out what it means for self-custody.

The Coldcard seed flaw: thoughts on trust and self-custody

A technical blunder left five years of Coldcard seeds guessable. On who's to blame, why I don't buy blaming AI, and what it means for self-custody.

Thanks for reading, and take care of your fellow Bitcoiners.

— Bennet